STS study of the CMR effect of a manganite thin film in an external magnetic field

TL;DR

This study investigates the colossal magnetoresistance (CMR) effect in a La0.75Ca0.25MnO3 thin film using scanning tunnelling microscopy and spectroscopy, revealing local magnetic field-dependent conductivity changes and electronic state redistribution.

Contribution

It provides a local spectroscopic analysis of the CMR effect in a manganite thin film under an external magnetic field, highlighting the electronic state redistribution.

Findings

Tunnelling conductivity is strongly enhanced at 4 T magnetic field.

Local surface spot exhibits magnetic field dependence of conductivity.

CMR behavior linked to redistribution of electronic states near Fermi energy.

Abstract

A La0.75Ca0.25MnO3-film grown by metalorganic aerosol deposition technique was investigated by scanning tunnelling microscopy and spectroscopy. A small spot was found on the surface which exhibits the expected magnetic field dependence of the tunnelling conductivity giving the opportunity for a local spectroscopic study of the intrinsic colossal magnetoresistance (CMR) behavior. The tunnelling conductivity is strongly enhanced in an external magnetic field of 4 T and the CMR behavior can be interpreted in terms of a redistribution of occupied electronic states torwards the Fermi energy.