55Mn NMR and magnetization studies of La0.67Sr0.33MnO3 thin films

TL;DR

This study uses 55Mn NMR and magnetization measurements to analyze the magnetic phases and anisotropies in La0.67Sr0.33MnO3 thin films, revealing interface and bulk behaviors and their magnetic responses.

Contribution

It provides new insights into the magnetic phase separation and anisotropy differences between interface and bulk regions in La0.67Sr0.33MnO3 thin films.

Findings

Two distinct NMR lines indicating interface and bulk phases.

Magnetization rotation dominates beyond the anisotropy field.

Different magnetic anisotropies at the interface and bulk.

Abstract

55Mn nuclear magnetic resonance and magnetization studies of the series of La0.67Sr0.33MnO3 thin films have been performed at low temperature. Two distinct lines were observed, at 322 MHz and 380 MHz, corresponding to two different phases, the former located at the interface, with localized charges, and the latter corresponding to the film bulk, with itinerant carriers (as it was also found in Ca manganite films). The spin-echo amplitude was measured as a function of a dc magnetic field applied either in the film plane or perpendicular to it. The field dependence of both the main NMR signal intensity and frequency shift is quite consistent with that calculated in a simple single domain model. The best fit to the model shows that magnetization rotation processes play a dominant role when the applied field exceeds the effective anisotropy field. Distinctly different magnetic anisotropies are deduced from the interface NMR signal.