Magnetic properties of ferrimagnetic Mn₃Si₂Se₆

The physical properties of Mn₃Si₂Se₆ have been investigated using single crystals grown by iodine-assisted vapor transport. The material possesses a ferrimagnetic ground state and the properties are similar to those in the isostructural compound Mn₃Si₂Te₆ . In these trigonal materials, the dominant magnetic exchanges are antiferromagnetic and intrinsically frustrated, leading to a variety of competing ground states. In Mn₃Si₂Se₆, the Curie temperature is T_C = 67(1) K, which is slightly lower than that of Mn₃Si₂Te₆ where T_C = 78 K. The anisotropy field is also smaller in the selenide relative to the telluride. In both materials, short-range correlations likely exist well-above T_C. Neutron single crystal diffraction data on Mn₃Si₂Se₆ suggest a collinear ferrimagnetic structure with the moments tilting out of the ab-plane in zero-field. Finally, the magnetization of vapor grown Mn₃Si₂Te₆ is shown for comparison; these vapor grown crystals do not show a sharp onset of magnetic anisotropy above 300 K as was previously observed for melt grown Mn₃Si₂Te₆ crystals.