Intrinsic Inhomogeneities in Manganite Thin Films Investigated with Scanning Tunneling Spectroscopy

TL;DR

This paper investigates the intrinsic spatial inhomogeneities in La0.7Sr0.3MnO3 thin films using scanning tunneling spectroscopy, revealing a domain structure that influences the metal-insulator transition and colossal magnetoresistance.

Contribution

It demonstrates how scanning tunneling spectroscopy can visualize and distinguish conducting and insulating domains in manganite thin films, elucidating their role in electronic phase transitions.

Findings

Identification of submicrometer conducting and insulating domains

Visualization of domain structure during metal-insulator transition

Evidence of percolation transition in domain connectivity

Abstract

Thin films of La0.7Sr0.3MnO3 on MgO show a metal insulator transition and colossal magnetoresistance. The shape of this transition can be explained by intrinsic spatial inhomogeneities, which give rise to a domain structure of conducting and insulating domains at the submicrometer scale. These domains then undergo a percolation transition. The tunneling conductance and tunneling gap measured by scanning tunneling spectroscopy were used to distinguish and visualize these domains.