Unusual electrical and magnetic properties in layered EuZn2As2

TL;DR

This study explores the magnetic and electrical properties of EuZn2As2, revealing antiferromagnetic order, ferromagnetic fluctuations, and field-induced spin reorientation, positioning it as a promising material for topological property investigations.

Contribution

It provides the first detailed investigation of EuZn2As2's magnetic structure and properties, highlighting its potential for topological studies in magnetic fluctuation and ordered regimes.

Findings

EuZn2As2 orders antiferromagnetically below 19 K.

Strong ferromagnetic fluctuations exist above TN.

Field-induced spin reorientation observed.

Abstract

Eu-based compounds often exhibit unusual magnetism, which is critical for nontrivial topological properties seen in materials such as EuCd2As2. We investigate the structure and physical properties of EuZn2As2 through measurements of the electrical resistivity, Hall effect, magnetization, and neutron diffraction. Our data show that EuZn2As2 orders antiferromagnetically with an A-type spin configuration below TN = 19 K. Surprisingly, there is strong evidence for dominant ferromagnetic fluctuations above TN, as reflected by positive Curie-Weiss temperature and extremely large negative magnetoresistance (MR) between TN and Tfl {\guillemotright} 200 K. Furthermore, the angle dependence of the MRab indicates field-induced spin reorientation from the ab-plane to a direction approximately 45{\deg} from the ab plane. Compared to EuCd2As2, the doubled TN and Tfl make EuZn2As2 a better platform for exploring topological properties in both magnetic fluctuation (TN < T < Tfl) and ordered (T < TN) regimes.