Spin-glass and random-field effects in exchange-biased NiFe film on a NiO single-crystal substrate

• Published in: Journal of applied physics Vol. 91; no. 10; pp. 7754 - 7756
• Main Authors: Araújo, A. E. P. de, Machado, F. L. A., Rodrigues, A. R., Azevedo, A., de Aguiar, F. M., de Almeida, J. R. L., Rezende, S. M., Egelhoff, W. F.
• Format: Journal Article
• Language: English
• Published: 15.05.2002
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.1447496

Magnetization (M) data on a ferromagnetic/antiferromagnetic (FM/AF) sample made of a permalloy thin film sputtered on a thick NiO single-crystal substrate reveal remarkable irreversibilities. The field, temperature (T), and time dependencies of M were measured after the sample was cooled in zero-field or in the presence of a field, keeping T below the Néel 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 glasses, in the parallel configuration it exhibits features of random-field systems. The observed metastabilities and thermal history dependencies are shown to result from frustrations and randomness due to the interface roughness.