Paramagnetic anisotropic magnetoresistance in thin films of SrRuO3

TL;DR

This study investigates the anisotropic magnetoresistance in thin films of SrRuO3 above its Curie temperature, revealing significant anisotropic effects in the paramagnetic state through Hall effect and magnetoresistance measurements.

Contribution

It introduces a detailed analysis of anisotropic magnetoresistance in SrRuO3 thin films in the paramagnetic phase, using magnetization expansion fitting to explain the observed effects.

Findings

Large anisotropic magnetoresistance observed in the paramagnetic state.

Resistivity extremum values are not aligned with magnetization directions.

Magnetoresistance correlates with the induced magnetization orientation.

Abstract

SrRuO3 is an itinerant ferromagnet and in its thin film form when grown on miscut SrTiO3 it has Tc of ~ 150 K and strong uniaxial anisotropy. We measured both the Hall effect and the magnetoresistance (MR) of the films as a function of the angle between the applied field and the normal to the films at temperatures above Tc. We extracted the extraordinary Hall effect that is proportional to the perpendicular component of the magnetization and thus the MR for each angle of the applied field could be correlated with the magnitude and orientation of the induced magnetization. We successfully fit the MR data with a second order magnetization expansion, which indicates large anisotropic MR in the paramagnetic state. The extremum values of resistivity are not obtained for currents parallel or perpendicular to the magnetization, probably due to the crystal symmetry.