Enhanced annealing stability of ferrimagnetic Tb/FeCo multilayers

In this study, we have investigated amorphous 20-nm-thick Tb/Fe80Co20 multilayer samples with different individual layer thicknesses and their corresponding alloy counterpart. particular, the structural magnetic properties were analyzed upon post-annealing. Up to a certain critical thickness of layers in multilayer, no significant difference between multilayers is observed as-deposited states, which indicates importance interfacial intermixing. With further increase layers, regions larger Tb content emerge, resulting reduced effective moment. The loss perpendicular anisotropy annealing seems be delayed for thin compared sample. We contribute behavior underlying anisotropic short-range order enforced by structure, hinders relaxation process. At higher temperatures, strongly intermix Fe Co diffuse through capping layer. This process leads strong enhancement saturation magnetization at temperature, due formation separated FeCo Tb-rich TbFeCo until sample gets oxidized.