Magnetic structure and crystal field excitations of NdOs2Al10: a neutron scattering study

C Ritter; D T Adroja; M D Le; Y Muro; T Takabatake

doi:10.1088/1361-648X/abee3b

Magnetic structure and crystal field excitations of NdOs₂Al₁₀: a neutron scattering study

J Phys Condens Matter. 2021 Apr 23;33(18). doi: 10.1088/1361-648X/abee3b.

Authors

C Ritter¹, D T Adroja^{2

3}, M D Le², Y Muro⁴, T Takabatake⁵

Affiliations

¹ Institut Laue-Langevin, 71 avenue des Martyrs, F-38042 Grenoble Cedex 9, France.
² ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxon, OX11 0QX, United Kingdom.
³ Physics Department, University of Johannesburg, PO Box 524, Auckland Park 2006, South Africa.
⁴ Faculty of Engineering, Toyama Prefectural University, Imizu 939-0398, Japan.
⁵ Quantum Matter Program, Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima, 739-8530, Japan.

PMID: 33711836
DOI: 10.1088/1361-648X/abee3b

Abstract

We have investigated the magnetic properties of a polycrystalline sample of NdOs₂Al₁₀using neutron diffraction and inelastic neutron scattering, magnetic susceptibility and heat capacity measurements. The magnetic susceptibility data reveal an antiferromagnetic transition atT_N1= 2.2 K while the heat capacity data which extend to lower temperatures show a further transition atT_N2= 1.1 K. The INS measurements detect four well-resolved crystal field excitations at 7.4, 12.4, 17.6 meV and 19.2 meV at 5 K. The positions and intensities of the observed CEF excitations and the temperature dependence of previously published single crystal susceptibility data are analysed based on the orthorhombic CEF model of theJ= 9/2 ground state multiplet of Nd³⁺ion. The neutron diffraction study reveals the magnetic structure atT= 1.6 K to be of sine wave type (κ= [0, 0.723, 0]) with an ordered state moment ofμ_Nd³⁺= 1.59(1)μ_Baligned along thea-axis in agreement with the single ion crystal field anisotropy. This indicates that the magnetism of NdOs₂Al₁₀is governed by the RKKY interactions in agreement with otherRT₂Al₁₀(R= Nd, Sm, Tb,T= Fe, Ru and Os), but different to that ofR= Ce based compounds where anisotropic two ions interaction as well as Kondo interaction govern the anomalous direction of the ordered state moment.

Keywords: NdOs2Al10; RKKY interaction; crystal electric field; magnetic structure; neutron scattering.