Study of CeNi4Mn by neutron diffraction

TL;DR

This study uses neutron diffraction to analyze the magnetic structure and atomic vibrations of CeNi4Mn, revealing Mn site occupancy, magnetic moments, and rattling phonon modes, contributing to understanding its ferromagnetic and transport properties.

Contribution

It provides the first detailed neutron diffraction analysis of CeNi4Mn, identifying Mn site occupancy, magnetic moments, and vibrational behavior, which were previously uncharacterized.

Findings

Mn atoms occupy the 4c site in the cubic structure.

Mn has a magnetic moment of 4.6 μ_B at 17 K.

Mn exhibits larger vibrational amplitude than Ce and Ni.

Abstract

We report neutron diffraction measurements on CeNi4Mn, which has recently been identified as a soft ferromagnet (Tc ~ 140 K) with a sizeable spin-transport polarization. Our data show conclusively that the Mn atoms occupy a unique site (4c) in the unit cell, which has the symmetry of the cubic MgCu4Sn-type structure. We infer a moment of 4.6 mu_B on Mn at 17 K, which is oriented ferromagnetically along the {101} plane. The amplitude of the Mn vibrational motion is found to be larger than that of Ce and Ni atoms at all temperatures, thereby lending support to theoretical prediction of rattling phonon modes in this compound.