Exchange bias in Cr/Gd multilayers with TC&lt;TN

Jiao, Zhiwei; Jiang, Wen; Si, Peng; Ye, G.X.

doi:10.1016/j.jallcom.2008.02.034

Cited by 14 publications

(4 citation statements)

References 27 publications

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“…() observed that the direction of H

_{E}

can be tuned by annealing or bombarding the NiO/NiCu bilayers in which T

_{C}

of NiCu is much lower than T

_{N}

of NiO. Previously, we reported the anomalous temperature effect on H

_{E}

for Cr/Gd bilayers () and Cr/Gd multilayers () where T

_{C}

of bulk Gd is slightly lower than

T_{N}

of bulk Cr and an unexpected enhancement of

H_{C}

in Tb/Cr multilayers with

T_{C} ≪ T_{N}

(). However, apart from the measured temperature, the magnetic properties of Cr/Gd multilayers influenced by other conditions have never been reported so far.…”

Section: Introductionmentioning

confidence: 96%

“…Based on these rich features of Gd and Cr, it can result in many novel magnetic properties of Cr/Gd film systems, as observed in Refs. . In this paper, we have investigated the measured temperature and the cooling field dependencies of exchange coupling in the [Cr/Gd]

_{5}

multilayers deposited at different temperatures, in order to enhance understanding of the magnetic properties for the AF/FM exchange bias systems.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Temperature and cooling field dependent exchange coupling in [Cr/Gd]₅ multilayers

Jiao

Chen

Jiang

et al. 2016

Physica Status Solidi (a)

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Exchange coupling has been investigated in the [Cr/Gd] 5 multilayers deposited at 25, 200, and 400 • C, where the Néel temperature (T N ) of antiferromagnetic Cr is slightly higher than the Curie temperature (T C ) of ferromagnetic Gd. It was found that the exchange coupling existed not only at T C < T < T N , but also above the temperature (T N ) of antiferromagnetic orderings with incommensurate spin-density wave structures transiting to paramagnetic state. These results can be discussed in terms of the crucial role played by the antiferromagnetic spins of Cr with commensurate spin-density wave structures in the vicinity of the Cr/Gd interfaces. Moreover, the exchange coupling of the multilayers grown at different temperatures exhibited different dependencies on the measuring temperature and the cooling field, respectively. Positive exchange bias was observed in the multilayers grown at 200 and 400 • C. The interfacial roughness, grain size, and the antiferromagnetic orderings of Cr may be responsible for the anomalous exchange coupling of the multilayers. In addition, the competition between the exchange coupling at Cr/Gd interfaces and the external field-Cr surface magnetic coupling can explain the appearance of negative or positive exchange bias.

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“…() observed that the direction of H

_{E}

can be tuned by annealing or bombarding the NiO/NiCu bilayers in which T

_{C}

of NiCu is much lower than T

_{N}

of NiO. Previously, we reported the anomalous temperature effect on H

_{E}

for Cr/Gd bilayers () and Cr/Gd multilayers () where T

_{C}

of bulk Gd is slightly lower than

T_{N}

of bulk Cr and an unexpected enhancement of

H_{C}

in Tb/Cr multilayers with

T_{C} ≪ T_{N}

(). However, apart from the measured temperature, the magnetic properties of Cr/Gd multilayers influenced by other conditions have never been reported so far.…”

Section: Introductionmentioning

confidence: 96%

_{5}

multilayers deposited at different temperatures, in order to enhance understanding of the magnetic properties for the AF/FM exchange bias systems.…”

Section: Introductionmentioning

confidence: 99%

Temperature and cooling field dependent exchange coupling in [Cr/Gd]₅ multilayers

Jiao

Chen

Jiang

et al. 2016

Physica Status Solidi (a)

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show abstract

“…Magnetically contrasted materials (MCM) like core‐shell nanowires,, or nanoparticles (NPs), consolidates,, ferrofluids, multilayers,, nanoclusters, etc., are composites consisting of two or more different magnetic phases. Chemical communion between these magnetic phases results in outstanding materials with enhanced magnetic behavior.…”

Section: Introductionmentioning

confidence: 99%

Magnetic Traits in CoO‐Core@CoFe₂O₄‐shell Like Nanoparticles

et al. 2019

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Antiferromagnetic (AF) CoO pseudo-single crystals 125 AE 20 nm in diameter were prepared by forced hydrolysis in polyol and used as seeds to grow a poly-and nanocrystalline (5 nm in diameter) ferrimagnetic (F) CoFe 2 O 4 shell. Transmission electron microscopy (TEM) showed a certain epitaxy between the face-centered cubic lattices of the AF rock-salt core and the F spinel shell. Magnetometry measurements do not evidence any exchange bias feature between the two phases in direct contact. The hysteresis loops recorded between 7 and À7 T after cooling the composite particles from 400 K (between the Néel and the Curie temperatures of the AF and F phases, respectively) to 5 K, with and without a cooling magnetic field (m 0 H FC = +7 T), are the same, meaning that the AF core does not allow any spin pinning on the CoFe 2 O 4 nanocrystals. Nevertheless, differences exist between these magnetic data and those collected on two CoFe 2 O 4 reference particles: the low temperature coercive field of the composite is between those of 5 nm sized single-crystals and their assembly as submicrometer polycrystals. This order was also observed for the blocking temperature, although the constituting CoFe 2 O 4 nanocrystals of all these particles, the composite and the two references, were the same. Advanced analysis by X-ray diffraction and TEM established that the coherent crystallographic domain length of the ferrite phase and the magnetic behavior of the three systems are interdependent. Depending on the growth conditions of the CoFe 2 O 4 phase, a relative epitaxy between the nanocrystals may exist. It is much greater in the polycrystalline CoFe 2 O 4 particles than in their CoOÀCoFe 2 O 4 core-shell counterparts, and does not occur in free single crystal CoFe 2 O 4 particles.[a] Dr.

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“…Quanto aos filmes de Gd/Cr, de nosso conhecimento, na literatura existem três trabalhos com menos de duas bicamadas [65][66][67], e três trabalhos com mais de duas bicamadas [68][69][70]. Sendo que, nas referências [68,69], assim como nos filmes multicamadas de Gd/W, é investigada principalmente a magnetização em função do campo magnético, e na referência [70] é investigada a estrutura magnética por polarização de nêutrons. Nesses trabalhos, as espessuras das camadas de Gd e Cr são de 3 a 102 nm e 1 a 90 nm, respectivamente.…”

Section: Introdução E Objetivosunclassified

Propriedades magnéticas de filmes multicamadas Gd/W e Gd/Cr depositados por sputtering

Fischer¹,

Moraes²

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Ao meu orientador, professor Mário Antônio Bica de Moraes, pelo incentivo, auxílio, ensinamentos, amizade e paciência durante todo o trabalho. Às agências financiadoras deste projeto, Capes, Fapesp, e especialmente CNPq pela concessão da bolsa sob o processo nº 140435/2006-9. Ao Francisco Paulo M. Rouxinol e ao Rogério V. Gelamo pela convivência e colaboração no trabalho de laboratório. Aos professores Sérgio Gama, Lisandro P. Cardoso e Flávio Gandra, e também ao Dr. Alexandre Magnus pelas valiosas discussões. Aos colegas George Loula Dourado, Ricardo dos Reis e ao técnico Dr. Adelino Coelho Aguiar pelo grande auxílio com os equipamentos PPMS e SQUID. Ao Alan Menezes pelas medidas de difração de raios-x. À professora Mônica A. Cotta pela disponibilidade do microscópio de força atômica e ao técnico João Hermes pelo auxílio com esse equipamento. Ao Alberto Moreau pelo programa de imagens. Aos técnicos Antônio Von Zuben e Carlos Salles pelas diversas vezes que me auxiliaram em trabalhos de laboratório. Ao Alfredo Rodrigues Vaz pelas imagens iniciais de microscopia eletrônica de varredura e novamente ao Rogério V. Gelamo por outras imagens por essa mesma técnica. Ao professor Richard Landers e à técnica Rita Vinhas pelas medidas de XPS. Ao Dr. Marcel Dupret e ao técnico Marcos Antônio do LAMFI/USP pelas medidas de RBS. Ao Douglas Soares e ao Gustavo Viana pelo transporte de amostras para tais medidas. Aos técnicos das oficinas mecânicas, Jorge L. Pires, aqui representando os funcionários da oficina central, e ao Orival F. da Silva (Jacaré) e ao André R. de Paula que sempre me ajudaram confeccionando peças. Aos funcionários da criogenia, Milton A. Silva e Eduardo V. A. da Silva, pelo fornecimento de hélio líquido e pelas inúmeras vezes que me auxiliaram com os pesados dewars. Aos funcionários da coordenação de pós-graduação: Maria Ignez, Armando, Gilvani e João Henrique, e às secretárias do departamento de física aplicada: Flávia, Heloisa e Márcia, pela tolerância, colaboração e eficiência. Aos funcionários da Biblioteca da Física e do Centro de Computação que sempre me atenderam prontamente. viii Aos coordenadores do Programa de Estágio Docente, professores Varlei Rodrigues, Edison Zacarias e Márcio Pudenzi, e aos colegas pós-graduandos que participaram comigo desse programa e que colaboraram para minha formação como professora. Novamente ao professor Mário Bica que, além de concordar com a minha participação nesse programa, auxiliou-me na execução de experimentos e proporcionou-me preciosas discussões em disciplina ministrada por mim. Ao Ezequiel C. Siqueira e ao Bruno Martins pelo companheirismo durante as disciplinas. À Elizabeth B. Andrade e à Sabrina Lino pela amizade e apoio nos últimos anos. Ao casal Tereza e Mauro Coelho, pela paciência, colaboração, compreensão e pela amizade que cultivamos nesses anos. Aos amigos mais recentes, Leandro Lodi e Sandra Sena, pela amizade, torcida e auxílio nesses últimos meses.

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Exchange bias in Cr/Gd multilayers with TC<TN

Cited by 14 publications

References 27 publications

Temperature and cooling field dependent exchange coupling in [Cr/Gd]₅ multilayers

Temperature and cooling field dependent exchange coupling in [Cr/Gd]₅ multilayers

Magnetic Traits in CoO‐Core@CoFe₂O₄‐shell Like Nanoparticles

Propriedades magnéticas de filmes multicamadas Gd/W e Gd/Cr depositados por sputtering

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Exchange bias in Cr/Gd multilayers with TC<TN

Cited by 14 publications

References 27 publications

Temperature and cooling field dependent exchange coupling in [Cr/Gd]5 multilayers

Temperature and cooling field dependent exchange coupling in [Cr/Gd]5 multilayers

Magnetic Traits in CoO‐Core@CoFe2O4‐shell Like Nanoparticles

Propriedades magnéticas de filmes multicamadas Gd/W e Gd/Cr depositados por sputtering

Contact Info

Product

Resources

About

Temperature and cooling field dependent exchange coupling in [Cr/Gd]₅ multilayers

Temperature and cooling field dependent exchange coupling in [Cr/Gd]₅ multilayers

Magnetic Traits in CoO‐Core@CoFe₂O₄‐shell Like Nanoparticles