# Magnetotransport properties of granular oxide-segregated CoPtCr films for applications in future magnetic memory technology

## TL;DR

This study investigates the magnetotransport properties of granular oxide-segregated CoPtCr films, revealing giant magnetoresistance effects at microscopic scales that could enhance future magnetic memory technologies.

## Contribution

It demonstrates the presence of tunnel magnetoresistance in CoPtCr films through combined bulk and point-contact measurements, highlighting potential for high-density magnetic recording.

## Key findings

- Bulk magnetoresistance less than 0.02%
- Giant magnetoresistance up to 50,000% at microscopic scale
- Magnetoresistance decreases with applied bias

## Abstract

Magnetotransport properties of granular oxide-segregated CoPtCr films were studied on both macroscopic and microscopic length scales by performing bulk and point-contact magnetoresistance measurements, respectively. Such a perpendicular magnetic medium is used in state-of-the-art hard disc drives and if combined with magnetoresistive phenomena (for read/write operations) may lead to a novel concept for magnetic recording with high areal density. While the bulk measurements on the films showed only small variations in dc resistance as a function of applied magnetic field (magnetoresistance of less than 0.02 %), the point-contact measurements revealed giant-magnetoresistance-like changes in resistance with up to 50,000 % ratios. The observed magnetorestive effect could be attributed to a tunnel magnetoresistance between CoPtCr grains with different coercivity. The tunneling picture of electronic transport in our granular medium was confirmed by the observation of tunneling-like current-voltage characteristics and bias dependence of magnetoresistance; both the point-contact resistance and magnetoresistance were found to decrease with the applied dc bias.

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Source: https://tomesphere.com/paper/1907.09675