Nd induced Mn spin-reorientation transition in NdMnAsO

TL;DR

This study investigates the magnetic and electronic properties of NdMnAsO, revealing a temperature-induced spin reorientation of Mn moments triggered by Nd ordering, with detailed structural, magnetic, and resistivity measurements.

Contribution

It provides the first detailed characterization of the Nd-induced Mn spin reorientation transition in NdMnAsO, combining multiple experimental techniques.

Findings

NdMnAsO is an antiferromagnetic semiconductor with TN = 359 K.

Mn moments reorient from c-axis to ab-plane at TSR = 23 K.

Electrical resistivity shows metallic behavior below 250 K with a semiconducting magnitude.

Abstract

A combination of synchrotron X-ray, neutron powder diffraction, magnetization, heat capacity and electrical resistivity measurements reveals that NdMnAsO is an antiferromagnetic semiconductor with large Neel temperature (TN = 359(2) K). At room temperature the magnetic propagation vector k = 0 and the Mn moments are directed along the crystallographic c-axis (mMn = 2.41(6) BM). Upon cooling a spin reorientation (SR) transition of the Mn moments into the ab-plane occurs (TSR = 23 K). This coincides with the long range ordering of the Nd moments, which are restricted to the basal plane. The magnetic propagation vector remains k = 0. At base temperature (1.6 K) the fitted moments are mab,Mn = 3.72(1) BM and mab,Nd = 1.94(1) BM. The electrical resistivity is characterized by a broad maximum at 250 K, below which it has a metallic temperature dependence but semiconducting magnitude (rho250K = 50 Ohm cm, residual resistivity ratio = 2), and a slight upturn at the SR transition.