Collinear ferromagnetism with reduced moment length in kagome magnet Nd3Ru4Al12

TL;DR

This study uses neutron diffraction to identify Nd3Ru4Al12 as a collinear ferromagnet with uniform magnetic moments, clarifying its magnetic ground state and supporting its anomalous Hall and Nernst effects.

Contribution

The paper establishes the magnetic ground state of Nd3Ru4Al12 as a collinear ferromagnet with uniform moments, correcting previous assumptions of unequal moments.

Findings

Identified the magnetic structure as collinear ferromagnet with Q=0.

Measured the uniform moment length as 2.1 μB/Nd.

Supported the magnetic state with polarized neutron scattering data.

Abstract

We determine the magnetic ground state of the kagome lattice magnet Nd3Ru4Al12 by single-crystal neutron diffraction, supported by experiments with polarized neutrons. We identify this material as a collinear ferromagnet ("hex-FM") with uniform moment length mc = 2.1 {\mu}B/Nd and ordering vector Q = 0, in contrast to a previous, seminal report that proposed unequal moment lengths on two Nd sites, here called the "ortho-FM" state. Our analysis of the flipping ratio in polarized neutron scattering is consistent with the hex-FM state. The results provide a microscopic basis for understanding the large fluctuation-induced Hall and Nernst responses near TC = 41 K, as previously reported for Nd3Ru4Al12.