Determining Curie temperature of (Ga,Mn)As samples based on electrical transport measurements: low Curie temperature case

TL;DR

This paper demonstrates that traditional resistivity peak methods fail for low-TC (Ga,Mn)As samples and proposes an alternative electrical transport measurement technique based on the second derivative of resistivity to determine Curie temperature.

Contribution

It introduces a new method using the temperature dependence of the second derivative of resistivity under magnetic field for low-TC (Ga,Mn)As samples.

Findings

Traditional peak method fails for non-metallic, low-TC samples.

Proposed method accurately determines Curie temperature in challenging samples.

Method based on second derivative of resistivity under magnetic field.

Abstract

In this paper we show that the widely accepted method of the determination of Curie temperature (TC) in (Ga,Mn)As samples, based on the position of the peak in the temperature derivative of the resistivity,completely fails in the case of non-metallic and low-TC unannealed samples. In this case we propose an alternative method, also based on electric transport measurements, which exploits temperature dependence of the second derivative of the resistivity upon magnetic field.