Exchange bias and spin glass behavior in biphasic NiFe2O4/NiO thin films

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:419

Article

Pebley, Andrew C.¹  Fuks, Preston E.²  Pollock, Tresa M.¹  Gordon, Michael J.² 

[1] Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA

[2] Univ Calif Santa Barbara, Dept Chem Engn, Santa Barbara, CA 93106 USA

关键词: Exchange bias;    Spin glass;    Microplasma;    Thin film deposition;   

DOI  :  10.1016/j.jmmm.2016.06.009

来源: Elsevier

【 摘 要 】

Magnetic exchange bias and coercivity of nanogranular NiFe2O4/NiO thin films, prepared using flow stabilized microplasmas and post-deposition annealing, have been investigated as a function of ferrimagnet/antiferromagnet phase fraction, grain size, and temperature. Exchange bias (EB) and vertical shifts in hysteresis loops observed in the as-deposited and low-T annealed (<= 600 degrees C) films were attributed to exchange coupling between nanocrystalline NiFe2O4 (similar to 8-10 nm) and a structurally-disordered spin glass (SG)-like phase. At higher annealing temperature (850 degrees C), the observed EB was found to arise from exchange coupling between NiFe2O4 and NiO, rather than a SG phase, most likely due to reduction of structurally-disordered interfaces and a substantial increase in NiFe2O4 grain size (similar to 26 nm). (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

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