Magnetic Behavior of Single La$_{0.67}$Ca$_{0.33}$MnO$_3$ Nanotubes: Surface and Shape Effects

TL;DR

This study investigates the magnetic properties of individual La$_{0.67}$Ca$_{0.33}$MnO$_3$ nanotubes, revealing shape-driven anisotropy and surface effects influencing magnetization, using highly sensitive micro-mechanical measurements.

Contribution

First measurement of magnetization loops in single La$_{0.67}$Ca$_{0.33}$MnO$_3$ nanotubes, highlighting shape and surface effects on magnetic behavior.

Findings

Magnetic anisotropy is shape-dependent.

Surface properties dominate temperature-dependent magnetization.

Achieved measurement of magnetization in nanotubes under 14 picograms.

Abstract

We report magnetization experiments in two magnetically isolated ferromagnetic nanotubes of perovskite La$_{0.67}$Ca$_{0.33}$MnO$_3$. The results show that the magnetic anisotropy is determined by the sample shape although the coercive field is reduced by incoherent magnetization reversal modes. The temperature dependence of the magnetization reveals that the magnetic behavior is dominated by grain surface properties. These measurements were acquired using a Silicon micro-mechanical oscillator working in its resonant mode. The sensitivity was enough to measure the magnetic properties of these two samples with a mass lower than 14 picograms and to obtain for the first time the magnetization loop for one isolated nanotube.