Elastic and Inelastic Neutron Scattering Study of the Triangular Lattice Ising Antiferromagnet TmMgGaO4*

The LnMgGaO₄ family of materials (with Ln= Yb³⁺, Er³⁺, and Tm³⁺) has been the focus of recent studies in frustrated magnetism due to the combination of anisotropic exchange interactions from strong spin obit coupling, geometrical frustration, and inherent site disorder of Mg²⁺ and Ga³⁺. In order to further understand the original compound, YbMgGaO4, we have begun to investigate how the non-Kramers ion Tm3+ differs from Yb3+ when placed in a similar crystal structure. TmMgGaO₄ displays a strong Ising behavior and magnetic scattering at the K-point of the triangular Brillouin zone at T= 0.05K. In this talk, I will present recent neutron scattering results on single-crystals of TmMgGaO₄ that elucidate the temperature and magnetic field dependence of spin correlations in that material.