Exchange Bias of Py-Based Ferromagnetic Multilayers Compared to Their Alloy

The objective of this experiment is to compare the exchange bias of a Py-based alloy film with several multilayer structures with both total thickness and net magnetization equal to the alloy. Samples were made via DC magnetron sputtering using permalloy (Py=Ni_0.8Fe_0.2) and Py_0.8Cu_0.2 as the ferromagnets in equal proportions to create an overall alloy of Py_0.9Cu_0.1 with a total thickness of 20 nm. The films are exchange biased by an 8 nm layer of IrMn and capped with a 5 nm layer of Ta to avoid oxidation. Py_0.9Cu_0.1 (20 nm)/IrMn vs. [Py_0.8Cu_0.2(t)/ Py(t)]_X/IrMn, where x ranges from 2 to 20 and t is chosen such that 2t*x = 20nm. In this presentation we discuss the results of magnetometry by comparing MOKE and VSM measurements to understand how the multilayer structures differ from the alloy.