Microphotoluminescence study of disorder in ferromagnetic (Cd,Mn)Te quantum well

TL;DR

This study uses microphotoluminescence mapping to analyze local disorder and its impact on spontaneous magnetization fluctuations in a ferromagnetic (Cd,Mn)Te quantum well, revealing carrier density fluctuations as the main influence.

Contribution

It provides the first local measurement linking carrier density fluctuations to magnetization variability in ferromagnetic quantum wells.

Findings

Carrier density fluctuations drive magnetization fluctuations.

Mn spin density fluctuations have negligible effect.

Local measurements correlate disorder with magnetic properties.

Abstract

Microphotoluminescence mapping experiments were performed on a modulation doped (Cd,Mn)Te quantum well exhibiting carrier induced ferromagnetism. The zero field splitting that reveals the presence of a spontaneous magnetization in the low-temperature phase, is measured locally; its fluctuations are compared to those of the spin content and of the carrier density, also measured spectroscopically in the same run. We show that the fluctuations of the carrier density are the main mechanism responsible for the fluctuations of the spontaneous magnetization in the ferromagnetic phase, while those of the Mn spin density have no detectable effect at this scale of observation.