Change of magnetic ground state by light electron-doping in CeOs2Al10

TL;DR

This study shows that light electron doping in CeOs2Al10 via Ir substitution significantly alters its magnetic ground state, increasing the ordered moments and changing the magnetic structure, highlighting electron doping as a key factor in magnetic property tuning.

Contribution

It demonstrates how minimal electron doping through Ir substitution can change the magnetic structure and ground state of CeOs2Al10, providing insights into magnetic behavior in Ce(Ru/Os)2Al10 compounds.

Findings

Magnetic structure changes with ~8% Ir doping

Ordered moments increase to 0.92 μ_B

Transition temperature decreases to 21K

Abstract

The effect of Ir substitution for Os in CeOs2Al10, with an unusually high Neel temperature of T~28.5K, has been studied by high-resolution neutron diffraction and magnetization measurements. A small amount of Ir (~ 8%) results in a pronounced change of the magnetic structure of the Ce-sublattice. The new magnetic ground state is controlled by the single ion anisotropy and implies antiferromagnetic arrangement of the Ce-moments along the a-axis, as expected from the anisotropy of the paramagnetic susceptibility. The value of the ordered moments, 0.92(1) mu_B, is substantially bigger than in the undoped compound, whereas the transition temperature is reduced down to 21K. A comparison of the observed phenomena with the recently studied CeRu1.9Rh0.1Al10 system, exhibiting similar behaviour [A. Kondo et al., J. Phys. Soc. Jpn. 82, 054709 (2013)], strongly suggests the electron doping as the main origin of the ground state changes. This provides a new way of exploring the anomalous magnetic properties of the Ce(Ru/Os)2Al10 compounds.