Experimental observation of an enhanced anisotropic magnetoresistance in non-local configuration

TL;DR

This study demonstrates that non-local magnetoresistance measurements in Ni nanostructures exhibit significantly larger AMR signals than local measurements, due to current spreading effects, which can be modeled in anisotropic conductors.

Contribution

The paper provides experimental evidence and modeling showing that non-local AMR signals are enhanced by current spreading in anisotropic conductors, a novel insight for spintronic measurements.

Findings

Non-local AMR signals are up to ten times larger than local signals.

Non-local AMR increases with greater separation between current and voltage regions.

Current spreading in anisotropic conductors explains the enhanced non-local AMR.

Abstract

We compare non-local magnetoresistance measurements in multi-terminal Ni nanostructures with corresponding local experiments. In both configurations, the measured voltages show the characteristic features of anisotropic magnetoresistance (AMR). However, the magnitude of the non-local AMR signal is up to one order of magnitude larger than its local counterpart. Moreover, the non-local AMR increases with increasing degree of non-locality, i.e., with the separation between the region of the main current flow and the voltage measurement region. All experimental observations can be consistently modeled in terms of current spreading in a non-isotropic conductor. Our results show that current spreading can significantly enhance the magnetoresistance signal in non-local experiments.