Spin Reorientation Transition and Exchange Bias in Hard/Soft Tb–Co/FeNi Films

Magnetization studies were carried out for Tb–Co thin films and Tb–Co/FeNi bilayers, prepared by magnetron sputtering technique. The composition of the Tb–Co films varied in the range of 19–24 at.%. All Tb–Co films were found to have perpendicular magnetic anisotropy in a wide temperature range. In addition, for some Tb–Co films, a spin reorientation transition was observed in the investigated temperature range. An analysis of the obtained results suggests that, in the course of deposition of the FeNi layer onto the Tb–Co layer, an interlayer magnetic boundary is formed, and its parameters depend on the composition of the Tb–Co layer. The magnetic structure peculiarities of this boundary determine the value of the exchange bias in Tb–Co/FeNi bilayers and its temperature dependence.