Measurement dependence of the exchange bias

Recently, in addition to the conventional hysteresis loop measurement, seve ral different measurement techniques, such as ac susceptibility, ferromagne tic resonance (FMR), and Brillouin light scattering, have been used to stud y the unidirectional exchange coupling induced in a ferromagnetic film in p roximity to an antiferromagnet. In this article, we theoretically investiga te how interface exchange coupling manifests itself in different measuremen ts. The magnetic degrees of freedom of the antiferromagnet are incorporated in this analysis. Anisotropies from hysteresis loop measurements, ac susce ptibility measurements, and FMR measurements are obtained. These results sh ow that the measured exchange anisotropies differ with measurement techniqu es. (C) 2000 American Institute of Physics. [S0021-8979(00)36508-2].