(Ca,Na)(Zn,Mn)2As2: a new spin & charge doping decoupled diluted ferromagnetic semiconductor with hexagonal CaAl2Si2 structure

TL;DR

This paper reports the synthesis of a new hexagonal diluted magnetic semiconductor, (Ca,Na)(Zn,Mn)2As2, exhibiting ferromagnetism up to 33 K and decoupled spin and charge doping, useful for studying spin-charge interactions.

Contribution

It introduces a novel spin- and charge-decoupled DMS with hexagonal structure and demonstrates its magnetic and electronic properties.

Findings

Ferromagnetic transition at 33 K with 10% Na doping

Observation of anomalous Hall effect below Curie temperature

Increased Mn doping leads to electron localization and resistivity minimum

Abstract

Here we report the successful synthesis of a spin- & charge-decoupled diluted magnetic semiconductor (Ca,Na)(Zn,Mn)2As2, crystallizing into the hexagonal CaAl2Si2 structure. The compound shows a ferromagnetic transition with a Curie temperature up to 33 K with 10% Na doping, which gives rise to carrier density of np~10^20 cm^-3. The new DMS is a soft magnetic material with HC<400 Oe. The anomalous Hall effect is observed below the ferromagnetic ordering temperature. With increasing Mn doping, ferromagnetic order is accompanied by an interaction between the local spin and mobile charge, giving rise to a minimum in resistivity at low temperatures and localizing the conduction electrons. The system provides an ideal platform for studying the interaction of the local spins and conduction electrons.