Study of Pseudo Spin Valves Based on $L1_{0}$ (111)-Oriented FePt and FePtCu Fixed Layer With Tilted Magnetocrystalline Anisotropy

Abstract

In this paper, we demonstrate a series of pseudo-spin-valve structures based on L1 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> (111)-oriented FePt and FePtCu with titled magnetocrystalline anisotropy. Highly ordered (111)-oriented L1 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> FePtCu with large anisotropy is achieved by optimizing the Cu content. Magnetoresistance (MR) up to 5% has been obtained by 1) optimizing the FePtCu growth using different underlayers, 2) enhancing the interface spin polarization using thin CoFe at the Cu interfaces, and 3) adjusting the Cu spacer thickness. The substantial MR realized with tilted fixed layer magnetization is an important prerequisite for the realization of tilted polarizer spin torque oscillators (STOs) or spin-transfer torque magnetoresistive random access memories (STT-MRAMs).