Significant enhancement of ferromagnetism in Zn$_{1-x}$Cr$_{x}$Te doped with iodine as an n-type dopant

TL;DR

This study demonstrates that iodine doping significantly enhances ferromagnetism in Zn$_{1-x}$Cr$_{x}$Te, increasing the Curie temperature up to 300K, despite the material remaining electrically insulating.

Contribution

It reveals that n-type doping with iodine boosts ferromagnetism in Zn$_{1-x}$Cr$_{x}$Te, highlighting the role of charge impurity doping in magnetic property enhancement.

Findings

Iodine doping raises the Curie temperature to 300K.

Ferromagnetism diminishes with p-type nitrogen doping.

Systematic correlation between charge impurity doping and ferromagnetism.

Abstract

The effect of additional doping of charge impurities was investigated in a ferromagnetic semiconductor Zn$_{1-x}$Cr$_{x}$Te. It was found that the doping of iodine, which is expected to act as an n-type dopant in ZnTe, brought about a drastic enhancement of the ferromagnetism in Zn$_{1-x}$Cr$_{x}$Te while the grown films remained electrically insulating. In particular, at a fixed Cr composition of x = 0.05, the ferromagnetic transition temperature Tc increased up to 300K at maximum due to the iodine doping from Tc = 30K of the undoped counterpart, while the ferromagnetism disappeared due to the doping of nitrogen as a p-type dopant. The observed systematic correlation of ferromagnetism with the doping of charge impurities of both p- and n-type, suggesting a key role of the position of Fermi level within the impurity d-state, is discussed on the basis of the double exchange interaction as a mechanism of ferromagnetism in this material.