Magnetic field tuned magnetic order and metamagnetic criticality in nonstoichiometric
Phys. Rev. B 113, 054432 – Published 20 February, 2026
DOI: https://doi.org/10.1103/1qcc-by7y
Abstract
We present a detailed study of magnetization, resistivity, heat capacity, and x-ray and neutron powder diffraction measurements performed on single crystals of nonstoichiometric , Au deficiency , a strongly correlated antiferromagnet with Néel temperature K. Field-dependent magnetization measurements reveal a large magnetic anisotropy at low temperatures with an easy axis along the crystallographic axis, in which direction a spin-flop transition exhibits strong features in magnetization, specific heat, and resistivity at kOe. The constructed temperature-field phase diagram connects this transition to the suppression of magnetic order, which evolves from a second-order nature into a first-order transition that bifurcates at the spin-flop transition into three transitions below 1 K. The smoothed nature of the metamagnetic transitions in nonstoichiometric is well described by an Ising model with weak quenched disorder, suggesting that the presence of Au vacancies is sufficient to smear the complex metamagnetic behavior and tune the critical behavior of magnetic order.