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Academic literature on the topic 'Strontium ferrite'

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Published: 4 June 2021
Last updated: 6 February 2022

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Journal articles on the topic "Strontium ferrite"

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de Campos, Marcos Flavio, and Daniel Rodrigues. "High Technology Applications of Barium and Strontium Ferrite Magnets." Materials Science Forum 881 (November 2016): 134–39. http://dx.doi.org/10.4028/www.scientific.net/msf.881.134.

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Ceramic magnets as barium ferrite or strontium ferrite have many applications in high technology. One of the reasons is the low cost when compared to competitor materials, as Alnico, MnBi, MnAl or NdFeB. In this study, the advantages and disadvantages of Ba and Sr ferrite magnets are discussed. One clear advantage is that ferrites are already oxides, and do not present the corrosion problems typical of NdFeB and other metallic alloys. As ferrites are oxides, the processing is much easier and cheaper. For example sintering can be done at air, and milling under wet condition. One of the main conclusions is the excellent ratio cost/benefit of ferrites, giving advantage in many applications. Special attention is given for application of ferrites in high efficiency motors.
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Huang, Shi Feng, Xue Li, Fu Tian Liu, Ya Mei Liu, Xin Cheng, and Zong Jin Li. "Influence of Strontium Ferrite on Properties of 0-3 Cement-Based Piezoelectric Composites." Key Engineering Materials 400-402 (October 2008): 125–29. http://dx.doi.org/10.4028/www.scientific.net/kem.400-402.125.

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0-3 cement based piezoelectric composites were fabricated using sulphoaluminate cement as matrix by compressing technique method. The effects of strontium ferrite content on the piezoelectric properties, dielectric properties and acoustic impedance of the composites were studied. The results show that the piezoelectric strain constant d33 and piezoelectric voltage constant g33 of the composites increase gradually with increaing strontium ferrite content. When the strontium ferrite mass fraction is 0.4%, both of the piezoelectric strain constant d33 and piezoelectric voltage constant g33 of the composite have the maximum value, and the values are 16.6pC•N-1 and 31.4mV•m•N-1, which are 35% and 19% larger than that of the composite without strontium ferrite doped, respectively. With the strontium ferrite content increase, both of the dielectric constant εr and the dielectric loss tanδ of the composites increase. With the addition of strontium ferrite the acoustic impedance Z increases, but there is no obvious relation between the strontium ferrite content and Z.
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Kikuchi, Takeyuki, Tatsuya Nakamura, Masamichi Miki, Makoto Nakanishi, Tatsuo Fujii, Jun Takada, and Yasunori Ikeda. "Synthesis of Hexagonal Ferrites by Citric Complex Method." Advances in Science and Technology 45 (October 2006): 697–700. http://dx.doi.org/10.4028/www.scientific.net/ast.45.697.

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Various hexagonal ferrites, which include hard and soft ferrites, were prepared by citric complex method. High purity reagent of strontium carbonate, iron (III) nitrate ennnahydrate, cobalt (II) nitrate hexahydrate and lanthanum oxide were used as starting materials. Prepared aqueous solution was heated for dehydration and gelling. Thermal pyrolysis was carried out by heating the gel. The obtained precursor powders were ground with an alumina mortar and compacted by uniaxial pressing into disk specimens and then heated at temperature range between 1023K and 1523K in air. Phase identification and determination of lattice parameters were carried out by powder X-ray diffraction. Scanning Electron Microscope was utilized to investigate the microstructure of the polycrystalline ferrites. Magnetic properties were discussed by magnetization measurements by using a vibration sample magnetometer. Magnetization and coercive force were measured. In the case of M-type ferrite, M-type barium and strontium ferrites were formed at vary low temperature relative to by conventional synthesis. The lanthanum and cobalt substituted M-type strontium ferrite ultra fine powders prepared by citric complex method showed extremely large coercive force.
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Aurélio Araujo Costa, Marcos, Edgar Roosevelt Braga-Filho, and Antônio Marcus Nogueira Lima. "Characterization And Control Of A Strontium Ferrite Motor." Eletrônica de Potência 20, no. 1 (February 1, 2015): 104–15. http://dx.doi.org/10.18618/rep.2015.1.104115.

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Chen, Nan Chun, Han Mei Ao, and Zhi Liang Zhan. "The Controlling Factors in the Content of Cr6+ in Green Strontium Ferrite." Materials Science Forum 610-613 (January 2009): 28–31. http://dx.doi.org/10.4028/www.scientific.net/msf.610-613.28.

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In order to reach the standard of the RoHS that the content of Cr6+ lower than 200ppm in ferrite, this reserch focused on the factors that influence on the content of Cr6+ during the preparation of Strontium Ferrite. The results show that the content of Cr6+ in Strontium Ferrit can be controlled among 91~117 ppm, and the optimum condition is as follows: the quality ratio of raw materials/graphite=10:1.25, the rate of the N2 flow 0.1~0.15 L/min, sintered temperature 950~1020°C, residence time 25~35min at the corresponding temperature point, granularity of the mixed system lower than 0.1~0.3mm.
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Liu, Chenglun, Longjun Xu, Xueyan Yang, Tiefeng Peng, and Jianjun Ren. "Preparation of strontium ferrite from strontium residue." Chinese Journal of Geochemistry 31, no. 1 (January 5, 2012): 74–77. http://dx.doi.org/10.1007/s11631-012-0551-9.

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Lu, Yi, Xin Chun Yang, Jin Lian Zhu, Fu Zhan Song, and Xiang Qian Shen. "Morphological and Magnetic Characteristics of Strontium Ferrite Micro- and Nanofibers." Advanced Materials Research 399-401 (November 2011): 736–40. http://dx.doi.org/10.4028/www.scientific.net/amr.399-401.736.

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Strontium ferrite micro- and nanofibers have been prepared by the sol-gel process and the electrospinning with diameters about 1 μm and 100 nm, respectively. Single phase strontium ferrite fibers are formed after calcined at 750 °C for 2 hours for both the sol-gel and electrospinning processes. These strontium ferrite fibers are fabricated of nanosized particles with a hexagonal plate-like morphology, which grow with the calcination temperature. The microfiber cross-section contains multi-nanoparticles whilst the nanofiber with a necklace-like morphology is linked by nanoparticles at the calcination temperature range from 850 to 1050 °C. The magnetic properties of strontium ferrite fibers are mainly influenced by the grain size and fiber diameter. Both the strontium ferrite micro- and nanofibers calcined at 900°C for 2 hours are fabricated from single-domain grains around 56 nm and exhibit the specific saturation magnetization of 60.8 A•m2•kg-1 (microfibers) and 59.9 A•m2•kg-1 (nanofibers) and coercivity of 361.9 kA•m-1 (micronfibers) and 523.6 kA•m-1 (nanofibers). The coercivity difference between the micro- and nanofibers can be attributed to the different shape anisotropy energies arising from various magnetization reversal behaviors for the micro- and nanofibers.
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Teh, Geok Bee, Yat Choy Wong, James Wang, Seng Gee Tan, and Balakrishnan Samini. "Effect of Sol-Gel Synthesis on the Structural and Photoluminescence Properties of Magnetoplumbite-Type Strontium Ferrite." Materials Science Forum 654-656 (June 2010): 1134–37. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.1134.

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Magnetoplumbite-type (M-type) strontium ferrite particles with two stoichiometric ratios (SrFexO19; x = 9.2 and 11.6) have been synthesized via the sol-gel technique employing ethylene glycol as the gel precursor. The prepared samples were characterized using x-ray diffractometry (XRD), thermogravimetric analysis (TGA), photoluminescence (PL) spectrophotometry, field emission scanning electron microscopy (FESEM), energy dispersive x-ray spectrometry (EDS) and superconductivity quantum interference device magnetometry (SQUID). X-ray powder diffraction patterns showed that the samples were single-phase with the space group of P63/mmc and cell parameter values of a = 5.88 Ǻ and c = 23.03 – 23.04 Ǻ. EDS results confirmed the composition being mainly of M-type SrFe12O19. The photoluminescence property of strontium ferrite was examined at excitation wavelength of 260 - 290 nm and significant PL emission peaks centered at 334 nm were detected. Both as-prepared strontium ferrites exhibited significant oxygen vacancies which were detectable via TGA where the sample with the Sr/Fe ratio of 1:11.6 exhibited the highest oxygen vacancies in its structure.
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Berthet, P., J. Berthon, G. Heger, and A. Revcolevschi. "Structure of metastable strontium ferrite." Materials Research Bulletin 27, no. 8 (August 1992): 919–24. http://dx.doi.org/10.1016/0025-5408(92)90190-b.

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Ahmad, Abid, Bhagyashree Mishra, Andrew Foley, Leslie Wood, and Maggie Yihong Chen. "High Permeability Photosintered Strontium Ferrite Flexible Thin Films." Micromachines 12, no. 1 (January 1, 2021): 42. http://dx.doi.org/10.3390/mi12010042.

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The paper is focused on the development and optimization of strontium ferrite nanomaterial and photosintered flexible thin films. These magnetic thin films are characterized with direct current (DC) and high frequency measurements. For photosintered strontium ferrite samples, we achieved relative complex permeability of about 29.5-j1.8 and relative complex permittivity of about 12.9-j0.3 at a frequency of 5.9 GHz.
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Dissertations / Theses on the topic "Strontium ferrite"

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Schmidt, Marek Wojciech, and Marek Schmidt@rl ac uk. "Phase formation and structural transformation of strontium ferrite SrFeOx." The Australian National University. Research School of Physical Sciences and Engineering, 2001. http://thesis.anu.edu.au./public/adt-ANU20020708.190055.

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Non-stoichiometric strontium iron oxide is described by an abbreviated formula SrFeOx (2.5 ≤ x ≤ 3.0) exhibits a variety of interesting physical and chemical properties over a broad range of temperatures and in different gaseous environments. The oxide contains a mixture of iron in the trivalent and the rare tetravalent state. The material at elevated temperature is a mixed oxygen conductor and it, or its derivatives,can have practical applications in oxygen conducting devices such as pressure driven oxygen generators, partial oxidation reactors in electrodes for solid oxide fuel cells (SOFC). ¶ This thesis examines the behaviour of the material at ambient and elevated temperatures using a broad spectrum of solid state experimental techniques such as: x-ray and neutron powder diffraction,thermogravimetric and calorimetric methods,scanning electron microscopy and Mossbauer spectroscopy. Changes in the oxide were induced using conventional thermal treatment in various atmospheres as well as mechanical energy (ball milling). The first experimental chapter examines the formation of the ferrite from a mixture of reactants.It describes the chemical reactions and phase transitions that lead to the formation of the oxide. Ball milling of the reactants prior to annealing was found to eliminate transient phases from the reaction route and to increase the kinetics of the reaction at lower temperatures. Examination of the thermodynamics of iron oxide (hematite) used for the reactions led to a new route of synthesis of the ferrite frommagnetite and strontium carbonate.This chapter also explores the possibility of synthesis of the material at room temperature using ball milling. ¶ The ferrite strongly interacts with the gas phase so its behaviour was studied under different pressures of oxygen and in carbon dioxide.The changes in ferrite composition have an equilibrium character and depend on temperature and oxygen concentration in the atmosphere. Variations of the oxygen content x were described as a function of temperature and oxygen partial pressure, the results were used to plot an equilibrium composition diagram. The heat of oxidation was also measured as a function of temperature and oxygen partial pressure. ¶ Interaction of the ferrite with carbon dioxide below a critical temperature causes decomposition of the material to strontium carbonate and SrFe12O19 . The critical temperature depends on the partial pressure of CO2 and above the critical temperature the carbonate and SrFe12O19 are converted back into the ferrite.The resulting SrFe12O19 is very resistant towards carbonation and the thermal carbonation reaction does not lead to a complete decomposition of SrFeOx to hematite and strontium carbonate. ¶ The thermally induced oxidation and carbonation reactions cease at room temperature due to sluggish kinetics however,they can be carried out at ambient temperature using ball milling.The reaction routes for these processes are different from the thermal routes.The mechanical oxidation induces two or more concurrent reactions which lead to samples containing two or more phases. The mechanical carbonation on the other hand produces an unknown metastable iron carbonate and leads a complete decomposition of the ferrite to strontiumcarbonate and hematite. ¶ Thermally and mechanically oxidized samples were studied using Mossbauer spectroscopy. The author proposes a new interpretation of the Sr4Fe4O11 (x=2.75) and Sr8Fe8O23 (x=2.875)spectra.The interpretation is based on the chemistry of the compounds and provides a simpler explanation of the observed absorption lines.The Mossbauer results froma range of compositions revealed the roomtemperature phase behaviour of the ferrite also examined using x-ray diffraction. ¶ The high-temperature crystal structure of the ferrite was examined using neutron powder diffraction.The measurements were done at temperatures up to 1273K in argon and air atmospheres.The former atmosphere protects Sr2Fe2O5 (x=2.5) against oxidation and the measurements in air allowed variation of the composition of the oxide in the range 2.56 ≤ x ≤ 2.81. Sr2Fe2O5 is an antiferromagnet and undergoes phase transitions to the paramagnetic state at 692K and from the orthorhombic to the cubic structure around 1140K.The oxidized formof the ferrite also undergoes a transition to the high-temperature cubic form.The author proposes a new structural model for the cubic phase based on a unit cell with the Fm3c symmetry. The new model allows a description of the high-temperature cubic form of the ferrite as a solid solution of the composition end members.The results were used to draw a phase diagramfor the SrFeOx system. ¶ The last chapter summarizes the findings and suggests directions for further research.
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Lepoittevin, Christophe. "Nouvelles ferrites de strontium présentant des structures complexes : synthèse et caractérisation structurale." Caen, 2006. http://www.theses.fr/2006CAEN2063.

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Ce travail de thèse est consacré à la recherche de nouvelles phases dans le système A-Sr-Fe-O (A = Bi ou Pb) riche en fer et à leur caractérisation structurale à l’aide de techniques telles que la microscopie électronique en transmission et la diffraction des rayons X sur poudre et sur monocristal. Le composé à l’origine de cette étude est le composé Sr4Fe6O13- dont la structure, déjà décrite il y a quelques années, consiste en l’alternance d’une simple couche perovskite [Sr2Fe2O6] avec une couche complexe [Sr2Fe4O7-delta]. Ce travail de thèse a permis de mettre en évidence et de comprendre des mécanismes structuraux complexes qui avaient été peu étudiés auparavant, puis d’exprimer cet oxyde sous la forme Fe2(Sr2)FeO6. 5-delta apparenté aux structures de type 2201. Les substitutions effectuées sur les sites Sr ont permis d’isoler quatre nouvelles phases. La première est l’oxyde Bi4Sr14Fe24O56, dont la caractérisation structurale a conduit à une description sous forme de doubles couches perovskite [(Bi,Sr)2Fe2O6]2 alternant avec une couche complexe [(Bi,Sr)2Fe4O7-delta]. Ce composé s’exprime sous la forme Fe2(Bi0. 69Sr1. 31)SrFe2O9. 5±delta/2, apparentée aux structures de type 2212. Une nouvelle phase obtenue par les substitutions sur le site Sr est la ferrite Pb4Sr13Fe24O53 dont la structure, dite en terrasses, résulte de l’intercroissance de quatre motifs 2201 avec trois motifs 2212 suivant la direction [203] de la sous-maille. Les deux dernières phases synthétisées et caractérisées structuralement sont les perovskites ordonnées déficitaires Bi1/3Sr2/3FeO2. 67 et Bi0. 5Ca0. 5FeO2. 75. Tous ces composés sont antiferromagnétiques associés à un comportement électrique de type semi-conducteur
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Morel, Antoine. "Amélioration des propriétés magnétiques des aimants permanents du type hexaferrite de strontium par la substitution lanthane - cobalt." Rouen, 2003. http://www.theses.fr/2003ROUES017.

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Les hexaferrites, en raison de leur faible coût et de leurs performances magnétiques, sont d'excellents matériaux pour produire des aimants permanents. Leur principale qualité est leur forte anisotropie magnétique uniaxiale. Leurs propriétés magnétiques peuvent être améliorées par substitution, notamment par la substitution lanthane-cobalt, comme le citent différents brevets apparus en 1998. Dans une première partie, nous avons, à l'aide de quatre techniques spectroscopiques (spectrométrie Mössbauer, spectroscopie Raman, résonance magnétique nucléaire et diffraction neutronique), étudié le positionnement de l'ion Co2+ dans la maille M des hexaferrites de composition Sr1-xLaxFe12-xCoxO19 synthétisées selon un procédé céramique classique. Les résultats montrent que l'ion Co2+ se place préférentiellement sur les sites octaédriques 4f2 et 2a. L'effet majeur observé sur les propriétés magnétiques intrinsèques est une forte augmentation du champ d'anisotropie magnétocristalline, mesuré par la méthode SPD (singular point detection), lorsque le taux de substitution augmente. Cet effet s'explique, à l'aide du " modèle de l'ion isolé " par la localisation de l'ion Co2+, lorsqu'il est associé à l'ion lourd La3+, sur les sites octaédriques dits " centraux " de la maille M. En outre, la dépendance en température du champ d'anisotropie magnétocristalline est fortement modifiée. La composition intrinsèquement la plus intéressante est Sr0,6La0,4Fe11,6Co0,4O19. L'étude des propriétés magnétiques des aimants montre une amélioration très significative. L'induction rémanente, la stabilité thermique et surtout le champ coercitif augmentent. En revanche, la rectangularité des courbes de désaimantation se dégrade. La composition optimale en terme de performances magnétiques, différente de l'optimum intrinsèque, est Sr0,8La0,2Fe11,8Co0,2O19. Cette différence s'explique par des effets microstructuraux antagonistes lorsque le taux de substitution devient supérieur à 0,2. En particulier, l'évolution du champ coercitif a été modélisée en tenant compte des évolutions microstructurales et des propriétés magnétiques intrinsèques. Enfin, dans le but de bénéficier pleinement des effets bénéfiques de cette substitution, les aimants ont été optimisés afin de corriger le défaut de rectangularité de leur courbe de désaimantation
Hexaferrites, due to their low cost combined with their magnetic properties, are excellent materials to produce permanent magnets. Their main quality is their high uniaxial magnetocrystalline anisotropy. As shown by different patents published in 1998, their magnetic properties can been improved by using the lanthanum-cobalt substitution. Firstly, using four spectroscopic methods (Mössbauer spectrometry, Raman spectroscopy, nuclear magnetic resonance and neutron diffraction), we localized the position of the Co2+ ion in the unit cell of the hexagonal M-type M phase in samples with the Sr1-xLaxFe12-xCoxO19 composition, synthesized with a classical ceramic process. The results show that Co2+ is localized in both 4f2 and 2a octahedral sites. The intrinsic magnetic properties are influenced by this substitution and the main effect is a strong increase of the magnetocristalline anisotropy field, as measured by the SPD (singular point detection) method, when the degree of substitution increases. This effect can be explained using the "single-ion model", and is attributed to the localization of the Co2+ ion, in relation with the presence of the La3+ ion, on the so-called "central" octahedral sites of the M unit cell. Moreover, the temperature dependence of the magnetocristalline anisotropy field is strongly modified. The most interesting intrinsic composition is Sr0. 6La0. 4Fe11. 6Co0. 4O19. The investigation of the magnet properties shows a significant improvement. The remanent induction, thermal stability and, mainly, coercive field increase. However, the squareness of the demagnetization curve decreases. The optimal composition giving the best final magnetic properties is Sr0. 8La0. 2Fe11. 8Co0. 2O19. This is different from the optimal intrinsic composition. This difference can be explained by negative microstructural effects when the degree of substitution is higher than 0. 2. Particularly, the behaviour of the coercive field has been accurately described by taking in account both microstrutural evolution and intrinsic magnetic properties. Finally, to take full benefit from the effects of this substitution, this magnets have been optimized to improve the squareness of their demagnetization curve
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Lee, Ching-Min, and 李景民. "The study and characterization of strontium-samarium ferrite and silicon carbide - conducting polyaniline core-shell materials." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/70506509722110982183.

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碩士
國防大學理工學院
應用化學碩士班
98
Over the past decade, the materials of microwave absorbers at high frequency region have already been further investigated and applied by the scientists. This thesis aims at the study of the multiple-component composite materials for the microwave absorption due to that the absorption of the single magnetic substance or single electric materials for the electromagnetic radiation of microwave was not satisfactory, yet on the contrary, a high absorption in microwave region(3-40 GHz) can be obtained on the special composite materials containing both of the magnetic loss and the electric loss. The Sol-gel method for the preparation of β-SiC was chosen as a energy-saving way in this study. M-type hexagonal ferrites and the Sr1-y(Sm)yFe12-xO19-1.5x+0.5y were synthesized by using the aqueous solution combustion synthesis. The characterizations and crystal structure identification of the intermediate and all powders annealed at different temperatures were investigated by FT-IR、TGA、DSC、XRD、UV-Vis、SEM、TEM and VSM. The microwave absorption properties of β-SiC/SrM/PANI absorbers were measured with the Vector Network Analyzer (Agilent Technologies E8362；HP 8733ES). The results of VSM measurements indicated that compound SrFe11O17.5 had the best magnetic properties. The saturated magnetization (Ms), the remnant magnetization (Mr) and Coertivity (Hc) of this compound are respectively Ms 64.135 (emu/g)、Mr 36.399 (emu/g) and Hc 1.341 (kOe). The X-ray diffraction pattern shows that the lattice constants a and c of M-type hexaferrites in this research are independent from the variation of Sr/Fe ratio. The values of a and c are about 5.88 Å and 23.02 Å, respectively. The microwave absorbers consists of 50 % SiC / 8 % SrFe11O17.5 / 1 % PANI / 41 % silicon resin. In the thickness of 2.5 mm，it had two strong reflection losses, the first reflection loss at 9.61 GHz is -32.2 dB and the second reflection loss at 38.1 GHz is -11.1 dB.
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Yu, Yang. "Surface segregation in strontium doped lanthanum cobalt ferrite: effect of composition, strain and atmospheric carbon dioxide." Thesis, 2016. https://hdl.handle.net/2144/17079.

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Solid oxide fuel cells (SOFCs) convert chemical energy directly into electrical energy, leading to significantly higher conversion efficiencies. The oxygen reduction reaction (ORR) at the cathode is often the rate-controlling step in the electrochemical reactions occurring in the SOFCs. Strontium doped lanthanum cobalt ferrite (LSCF) is a widely used cathode material due to its high electronic and ionic conductivity, and reasonable oxygen surface exchange coefficient. However, LSCF can have long-term stability issues such as surface segregation of Sr during SOFC operation, which can adversely affect the electrochemical performance. Thus, understanding the nature of the Sr surface segregation phenomenon, and how it is affected by the composition of LSCF, strain, and the CO2 in the gas phase at the cathode, are critical. In this research, heteroepitaxial thin films of La1-x SrxCo0.2Fe0.8O3- with various Sr contents (x = 0.4, 0.3, 0.2) were deposited by Pulsed Laser Deposition (PLD) on single crystal NdGaO3, SrTiO3 and GdScO3 substrates, leading to different strains in the films. The extent of Sr segregation at the film surface was quantified using the synchrotron-based total reflection X-ray fluorescence (TXRF) technique, and by Atomic Force Microscopy (AFM). The microstructure and the electronic structure of the Sr-rich phases formed on the surface were investigated by scanning/transmission electron microscopy (S/TEM) and hard X-ray photoelectron spectroscopy (HAXPES), respectively. These studies revealed that the surface phases consisted of SrO covered with a capping layer of SrCO3. The presence of CO2 in the atmosphere was found to enhance the kinetics of Sr surface segregation in LSCF. The extent of Sr segregation was found to be a function of the Sr content in bulk. Lowering the Sr content from 40% to 30% reduced the surface segregation, but further lowering the Sr content to 20% increased the segregation. The strains of LSCF thin films on various substrates were measured using high-resolution X-ray diffraction (HRXRD) and the Sr surface segregation was found to be reduced with compressive strain and enhanced with tensile strain present within the thin films. A model was developed correlating the Sr surface segregation with Sr content and strain effects to explain the experimental results.
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Roy, Debangsu. "Exchange Spring Behaviour in Magnetic Oxides." Thesis, 2012. http://hdl.handle.net/2005/3172.

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When a permanent magnet is considered for an application, the quantity that quantifies the usability of that material is the magnetic energy product (BH)max. In today’s world, rare earth transition metal permanent magnets like Nd-Fe-B, Sm-Co possesses the maximum magnetic energy product. But still for the industrial application, the ferrite permanent magnets are the primary choice over these rare transition metal magnets. Thus, in the present context, the magnetic energy product of the low cost ferrite system makes it unsuitable for the high magnetic energy application. In this regard, exchange spring magnets which combine the magnetization of the soft phase and coercivity of the hard magnetic phases become important in enhancing the magnetic energy product of the system. In this thesis, the exchange spring behaviour is reported for the first time in hard/soft oxide nanocomposites by microstructural tailoring of hard Barium Ferrite and soft Nickel Zinc Ferrite particles. We have analyzed the magnetization reversal and its correlation with the coercivity mechanism in the Ni0.8Zn0.2Fe2O4/BaFe12O19 exchange spring systems. Using this exchange spring concept, we could enhance the magnetic energy product in Iron Oxide/ Barium Calcium Ferrite nanocomposites compared to the bare hard ferrite by ~13%. The presence of the exchange interaction in this nanocomposite is confirmed by the Henkel plot. Moreover, a detailed Reitveld study, magnetization loop and corresponding variation of the magnetic energy product, Henkel plot analysis and First Order Reversal Curve analysis are performed on nanocomposites of hard Strontium Ferrite and soft Cobalt Ferrite. We have proved the exchange spring behaviour in this composite. In addition, we could successfully tailor the magnetization behaviour of the soft Cobalt Ferrite- hard Strontium Ferrite nanocomposite from non exchange spring behaviour to exchange spring behaviour, by tuning the size of the soft Cobalt Ferrite in the Cobalt Ferrite/Strontium Ferrite nanocomposite. The relative strength of the interaction governing the magnetization process in the composites has been studied using Henkel plot and First Order Reversal Curve method. The FORC method has been utilized to understand the magnetization reversal behaviour as well as the extent of the irreversible magnetization present in both the nanocomposites, having smaller and larger particle size of the Cobalt Ferrite. It has been found that for the all the studied composites, the pinning is the dominant process for magnetization reversal. The detailed structural analysis using thin film XRD, angle dependent magnetic hysteresis and remanent coercivity measurement, coercivity mechanism by micromagnetic analysis and First Order Reversal Curve analysis are performed for thin films of Strontium Ferrite which are grown on c-plane alumina using Pulsed Laser Deposition (PLD) at two different oxygen partial pressures. The magnetic easy directions of both the films lie in the out of plane direction where as the in plane direction corresponds to the magnetic hard direction. Depending on the oxygen partial pressure during deposition, the magnetization reversal changes from S-W type reversal to Kondorsky kind of reversal. Thus, the growth parameter for the Strontium Ferrite single layer which will be used further as a hard layer for realizing oxide exchange spring in oxide multilayer, is optimized. The details of the magnetic and structural properties are analyzed for Nickel Zinc Ferrite thin film grown on (100) MgAl2O4. We have obtained an epitaxial growth of Nickel Zinc Ferrite by tuning the growth parameters of PLD deposition. The ferromagnetic resonance and the angle dependent hysteresis loop suggest that, the magnetic easy direction for the soft Nickel Zinc Ferrite lie in the film plane whereas the out of plane direction is the magnetic hard direction. Using the growth condition of respective Nickel Zinc Ferrite and Strontium Ferrite, we have realized the exchange spring behaviour for the first time in the trilayer structure of SrFe12O19 (20 nm)/Ni0.8Zn0.2Fe2O4(20 nm)/ SrFe12O19 (20 nm) grown on c-plane alumina (Al2O3) using PLD. The FORC distribution for this trilayer structure shows the single switching behaviour, corresponding to the exchange spring behaviour. The reversible ridge measurement shows that the reversible and the irreversible part of the magnetizations are not coupled with each other.
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Books on the topic "Strontium ferrite"

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Basabe, Jacqueline. Gel-processing of strontium ferrite. Manchester: University of Manchester, 1993.

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Book chapters on the topic "Strontium ferrite"

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Miyajima, Naoki, Kazuyuki Akasaka, Takeshi Waki, Yoshikazu Tabata, Yoshinori Kobayashi, and Hiroyuki Nakamura. "Mössbauer effect of Ni-doped strontium ferrite." In ICAME 2011, 411–14. Dordrecht: Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-4762-3_69.

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Menushenkov, V. P., VS Shubakov, and S. V. Ketov. "Magnetic Properties of Strontium Ferrite Prepared Using Submicron-Sized SrFe12-xAlxO19Powders." In Energy Technology 2012, 275–79. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118365038.ch33.

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Patrakeev, M. V., J. A. Shilova, E. B. Mitberg, A. A. Lakhtin, I. A. Leonidov, and V. L. Kozhevnikov. "Oxygen Intercalation in Strontium Ferrite: Evolution of Thermodynamics and Electron Transport Properties." In New Trends in Intercalation Compounds for Energy Storage, 565–72. Dordrecht: Springer Netherlands, 2002. http://dx.doi.org/10.1007/978-94-010-0389-6_50.

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Effendi, M., Untung, W. T. Cahyanto, and W. Widanarto. "Characterization of Microwave Absorber Material Based on Strontium Samarium Ferrite Produced by Hybrid Sol-Gel Method." In Proceedings of the 6th International Conference and Exhibition on Sustainable Energy and Advanced Materials, 703–11. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-4481-1_67.

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Paulin Filho, P. I., and R. R. Corrêa. "Characterization of Strontium Ferrites Powders Obtained by High Energy Milling." In Advanced Powder Technology IV, 311–15. Stafa: Trans Tech Publications Ltd., 2005. http://dx.doi.org/10.4028/0-87849-984-9.311.

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Wang, Y. M., T. C. Chen, and H. Y. Chang. "Interface-Matching for Barium Strontium Ferrate-Ceria by Drop-Coating Buffer Layer." In Advances in Solid Oxide Fuel Cells and Electronic Ceramics II, 113–22. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2017. http://dx.doi.org/10.1002/9781119320197.ch10.

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Randhawa, B. S., and Manpreet Kaur. "Application of Mössbauer spectroscopy to the thermal decomposition of strontium and barium bis(CITRATO)Ferrates(III)." In ICAME 2007, 1329–35. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-78697-9_184.

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Zhou, Yong, Zhixiong Huang, Yan Qin, and Guangwu Zhang. "Preparation and electromagnetic properties of La3+ doped W-type strontium ferrite." In Advances in Energy Equipment Science and Engineering, 2835–38. CRC Press, 2015. http://dx.doi.org/10.1201/b19126-550.

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"The analysis of Gd/Sm–Mn substitution on the phase composition of strontium ferrite." In Information Science and Electronic Engineering, 75–78. CRC Press, 2016. http://dx.doi.org/10.1201/9781315265278-21.

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Syazwan Mustaffa, Muhammad, Rabaah Syahidah Azis, and Sakinah Sulaiman. "Dependence of pH Variation on the Structural, Morphological, and Magnetic Properties of Sol-Gel Synthesized Strontium Ferrite Nanoparticles." In Sol-Gel Method - Design and Synthesis of New Materials with Interesting Physical, Chemical and Biological Properties. IntechOpen, 2019. http://dx.doi.org/10.5772/intechopen.80667.

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Conference papers on the topic "Strontium ferrite"

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Nishio, H., H. Taguchi, F. Hirata, and T. Takeishi. "Magnetic Viscosity In Strontium Ferrite Fine Particles." In 1993 Digests of International Magnetics Conference. IEEE, 1993. http://dx.doi.org/10.1109/intmag.1993.642186.

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Chakraborty, Soma, Nidhi S. Bhattacharyya, and Satyajib Bhattacharyya. "X-band composite microwave absorber using doped strontium ferrite." In 2017 IEEE Applied Electromagnetics Conference (AEMC). IEEE, 2017. http://dx.doi.org/10.1109/aemc.2017.8325679.

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Morisako, A., M. Matsumoto, S. Takei, T. Yamazaki, and S. Morozumi. "Preparation Of C-axis Oriented Strontium Ferrite Thin Film." In 1997 IEEE International Magnetics Conference (INTERMAG'97). IEEE, 1997. http://dx.doi.org/10.1109/intmag.1997.597911.

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Ramamurthy Acharya, B., N. Venkatarmnani, S. Prasad, S. N. Shringi, R. Krishnan, M. Tessier, and E. Dumond. "Preparation and magnetic studies of strontium ferrite thin films." In 1993 Digests of International Magnetics Conference. IEEE, 1993. http://dx.doi.org/10.1109/intmag.1993.642081.

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Singh, Jasbir, Charanjeet Singh, Rajat Joshi, and S. Bindra Narang. "Microwave Attenuation of Cobalt-Tin Substituted Barium-Strontium Hexagonal Ferrite." In 2018 International Conference on Intelligent Circuits and Systems (ICICS). IEEE, 2018. http://dx.doi.org/10.1109/icics.2018.00054.

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Wu, Jian-gong, Quan-lu Li, Hui Xin, Peng-fei Wang, and Yong Wang. "Structural and dielectric properties of cobalt-copper ferrite/barium-strontium titanate composites." In 2008 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA). IEEE, 2008. http://dx.doi.org/10.1109/spawda.2008.4775836.

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Costa, Marcos A. A., Edgar R. Braga-Filho, and Antonio M. N. Lima. "AC motor drive system based on a custom designed strontium ferrite motor." In 2013 Brazilian Power Electronics Conference (COBEP 2013). IEEE, 2013. http://dx.doi.org/10.1109/cobep.2013.6785213.

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Jaiswal, Shivendra Kumar, and Jitendra Kumar. "Sol-Gel Synthesis and Magnetic, Optical and Impedance Behaviour of Strontium Ferrite Powder." In ASME 2011 International Manufacturing Science and Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/msec2011-50067.

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Abstract:
An attempt has been made to synthesize SrFeO3-δ powder by sol-gel process involving oxalate formation, its digestion for 4h, drying at 150°C for 24h, and decomposition at 800°C for 10h. The resulting powder is shown to a) exhibit a single phase with a perovskite-type cubic structure and lattice parameter a = 3.862±0.002A˚, b) contain irregular shape particles, and c) display optical absorption peaks corresponding to charge transfer from oxygen to iron (3.73 and 3.41eV), t2g to eg transition of Fe3+ (1.57eV), and crystal field (3d-3d) charge transfer of Fe3+ (1.25eV). Impedance over a wide frequency range of 20Hz-2MHz at 118–318K has contributions from two parallel ‘RC’ circuits belonging to bulk and grain boundaries with the later displaying significant space charge polarization. The relaxation time of polarization follows an Arrhenius behaviour (τ = τo exp[Ea/kBT]) with τo as ∼10−8s and activation energy Ea as ∼50meV. Further, the sample having magnetic character with transition temperature as 853K, coercivity (Hc) = 3748Oe and magnetization 0.09 μB per iron atom (at 17kOe). The zero field cooled and field cooled magnetization versus temperature data in conjunction with constricted hysteresis loops near the origin suggest core-shell morphology for the particles, core being antiferromagnetic with net uncompensated moment and shell conforming to disordered disposition of spins.
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Haselmann, Ulrich. "Ca segregation towards an in-plane compressive strain Bismuth Ferrite – Strontium Titanate interface." In European Microscopy Congress 2020. Royal Microscopical Society, 2021. http://dx.doi.org/10.22443/rms.emc2020.681.

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Lin, Mi, and Mohammed N. Afsar. "Measurement of Dielectric and Magnetic Characteristics of Nickel Ferrite and Strontium Ferrite Composite from 4.5 to 26.5 GHz Frequency Range." In 2006 IEEE Instrumentation and Measurement Technology. IEEE, 2006. http://dx.doi.org/10.1109/imtc.2006.328539.

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Reports on the topic "Strontium ferrite"

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Yamada, R., W. Foster, F. Ostiguy, and M. Wake. Recycler model magnet test on temperature compensation for strontium ferrite. Office of Scientific and Technical Information (OSTI), October 1995. http://dx.doi.org/10.2172/123259.

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