Low temperature magnetic structure of the quasi 1-dimensional magnet Ni2SiO4

TL;DR

This study investigates the low-temperature magnetic structure of Ni2SiO4, revealing complex magnetic interactions and moment canting through neutron diffraction analysis, contributing to understanding quasi-one-dimensional frustrated magnets.

Contribution

It provides the first detailed magnetic structure of Ni2SiO4 using neutron diffraction and symmetry analysis, highlighting the coexistence of ferromagnetic and antiferromagnetic interactions.

Findings

Magnetic ordering occurs below ~34 K.

Magnetic structure shows both ferromagnetic and antiferromagnetic interactions.

Moment canting indicates competing magnetic interactions.

Abstract

Ni2SiO4, Liebenbergite, is an example of a quasi-one-dimensional magnet made up of frustrated corner sharing triangles of Ni2+ (S = 1) ions that propagate parallel to the b axis. Ni2SiO4 is isostructural with olivine, a common mineral of varying composition Fe2-xMgxSiO4, and is described in the orthorhombic space group Pnma. A synthetic polycrystalline sample of Ni2SiO4 was studied using constant wavelength powder neutron diffraction. Diffraction spectra were collected above and below the antiferromagnetic ordering transition (TN ~ 34 K) and were used to refine the atomic and magnetic structures of Ni2SiO4. Corepresentational theory was used to determine the symmetry-allowed magnetic structures after the Neel transition and the refned magnetic structure evidences both ferromagnetic and antiferromagnetic inter-chain interactions, and ferromagnetic intra-chain coupling. The competition between the magnetic interactions can be seen in the canting of the moments away from a collinear arrangement.