Tunneling anisotropic magnetoresistance in multilayer-(Co/Pt)/AlOx/Pt structures

TL;DR

This paper investigates tunneling anisotropic magnetoresistance (TAMR) in multilayer-(Co/Pt)/AlOx/Pt structures, revealing significant effects depending on electrode termination and supported by ab initio calculations.

Contribution

It demonstrates enhanced TAMR effects in specific multilayer structures and provides theoretical insights into the underlying electronic states.

Findings

TAMR saturates at 0.15% in Co-terminated stacks

Order-of-magnitude TAMR enhancement with Pt-terminated electrodes

Strong dependence of TAMR on magnetic field, temperature, and bias

Abstract

We report observations of tunneling anisotropic magnetoresitance (TAMR) in vertical tunnel devices with a ferromagnetic multilayer-(Co/Pt) electrode and a non-magnetic Pt counter-electrode separated by an AlOx barrier. In stacks with the ferromagnetic electrode terminated by a Co film the TAMR magnitude saturates at 0.15% beyond which it shows only weak dependence on the magnetic field strength, bias voltage, and temperature. For ferromagnetic electrodes terminated by two monolayers of Pt we observe order(s) of magnitude enhancement of the TAMR and a strong dependence on field, temperature and bias. Discussion of experiments is based on relativistic ab initio calculations of magnetization orientation dependent densities of states of Co and Co/Pt model systems.