Crystal Structure, Charge Transport, and Magnetic Properties of MnSb2Se4

A single phase of MnSb2Se4 was synthesized by combining high-purity elements at 773 K. Single-crystal X-ray diffraction revealed that MnSb2Se4 is isostructural with FeSb2Se4 crystallizing in the monoclinic space group C2/m with a = 13.076(3) angstrom, b = 3.965(2) angstrom, c = 15.236(4) angstrom, beta = 115.1(2)degrees, Z = 4. MnSb2Se4 melts congruently at 790 K and is thermally stable up to 1000 K. Electronic band structure calculations, infrared diffuse reflectance spectroscopy, and low-temperature electronic transport data indicate that MnSb2Se4 is a narrow-bandgap p-type semiconductor with an energy bandgap of approximately 0.31 eV and exhibits a sharp increase in the resistivity near 230 K. A large Seebeck coefficient (S = +945 mu V K-1), high electrical resistivity (rho approximate to 9 Omega m), and low thermal conductivity (kappa = 1.4 Wm(-1) K-1) were observed at 300 K. Direct current (DC) magnetic-susceptibility measurements indicated that MnSb2Se4 is paramagnetic at 300 K and undergoes an order/disorder antiferromagnetic transition with a Neel temperature of approximately 20 K. Alternating current (AC) susceptibility at various frequencies suggested a spin-glass-like behavior.