Impact of Synthetic Ferrimagnetic Free Layers on Current-in-Plane Giant Magnetoresistance

Giant magnetoresistance (GMR) in spin valves, with broad applications in sensing and computing technologies, depends sensitively on the constituent layers. While spin valves with a simple ferromagnetic free layer have been studied extensively, the GMR response of spin valves with a more complex composite free layer is less well understood.

This study explores current-in-plane GMR in a spin-valve system composed of a Co/Cr/Co synthetic antiferromagnet (SAF) as the hard layer and a Co/Cr/Co synthetic ferrimagnet (SF) as the free layer. We investigate how the GMR ratio is affected by the degree of compensation in the SF free layer. Preliminary results demonstrate that altering the Co thickness ratio in the Co/Cr/Co free layer changes the polarity of GMR at compensation point, whereas the magnitude of the GMR shows little change. Our findings aim to enhance the understanding of magnetic interactions in emerging spintronic applications, such as an easy-plane spin torque oscillator leveraging a synthetic ferrimagnetic free layer [1].

[1]- Kubler, D., et al. . Large-Amplitude, Easy-Plane Spin-Orbit Torque Oscillators Driven by Out-of-Plane Spin Current arXiv:2407.00895,2024