Exchange bias in spin glass (FeAu)/NiFe thin films

The exchange bias of a ferromagnet in contact with a spin glass is evidenced in the sputter deposited (Fe 9.6 at. % Au)/NiFe bilayers. The biasing field decreases as temperature increases, change the sign after reaching a compensation temperature (T(o)), and are reduced to zero at higher temperatures. Furthermore, T(o) decreases with the decreasing FeAu layer thickness. Likewise, the inverse bias decreases with the increasing maximum field of a hysteresis loop. A spin structure model is suggested to explain our data. The results confirm the robust nature of the inverse bias in spin glass/ferromagnetic structure and reveal distinct physics from conventional antiferromagnetic/ferromagnetic systems. (C) 2010 American Institute of Physics. [doi:10.1063/1.3399780]