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Spin-Glass and Random-Field Effects in Exchanged-Biased NiFe Film on a NiO Single-Crystal Substrate



A E P de Araujo, F L. Machado, A R. Rodrigues, A Azevedo, F M. de Aguiar, J R. de Almeida, S M. Rezende, William F. Egelhoff Jr.


SQUID magnetometry measurements on a ferromagnetic/antiferromagnetic sample made of a permalloy thin film sputtered on a thick NiO single-crystal substratre reveal remarkable irreversibilities in the magnetization (M) versus temperature (T) data. The field, temperature and time dependences of M were measured after the sample had been cooled in zero-field or in the presence of a field, keeping T below the Neel temperature, with the field applied in the plane, either perpendicular or parallel to the anisotropy direction. While the behavior observed in the perpendicular configuration is characteristic of spin-glass systems, in the parallel configuration it exhibits features of random-field systems. The observed metastabilities and thermal history dependences are shown to result from frustrations and randomness due the the interface roughness, lending support to the random-field model for the exchange anisotropy in FM/AF bilayers.
Journal of Applied Physics
No. 10


exchange bias permalloy, nickel oxide, spin glass random field


de Araujo, A. , Machado, F. , Rodrigues, A. , Azevedo, A. , de Aguiar, F. , de Almeida, J. , Rezende, S. and Egelhoff Jr., W. (2002), Spin-Glass and Random-Field Effects in Exchanged-Biased NiFe Film on a NiO Single-Crystal Substrate, Journal of Applied Physics (Accessed May 26, 2024)


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Created April 30, 2002, Updated October 12, 2021