Crystal Growth and Magnetic Properties of LaMn0.91Sb2 and NdMn0.88Sb2

In this work, single crystals of LaMn0.91Sb2 and NdMn0.88Sb2 with deficiencies of Mn have been successively grown by using the Bi-flux method. They all crystallize in the HfCuSi2-type tetragonal structure with space group P4/nmm (No.129). LaMn0.91Sb2 displays signs of successive antiferromagnetic transitions around 133 and 108 K for H||c. In the case of Hic, LaMn0.91Sb2 shows signs of weak ferromagnetic transition around 138 K and antiferromagnetic transition at 56 K. However, there is no anomaly observed in the temperaturedependent specific heat curve. For NdMn0.88Sb2 measured with H||c, the Mn sublattice orders antiferromagnetically below 170 K and the Nd sublattice shows successive antiferromagnetic orders at 34 and 26 K. The antiferromagnetic state of Nd sublattice can be induced to be a ferromagnetic state through a spin-flop transition at 2 K. When Hic, the Mn sublattice displays antiferromagnetic orders at 171, 156, and 74 K. The Nd sublattice orders antiferromagnetically below 32 K. Ferromagnetic state for the Nd sublattice is induced by magnetic fields through a spin-flop transition at 2 K. Magnetic phase diagrams for NdMn0.88Sb2 are depicted for cases of H||c and Hic, respectively. LaMn0.91Sb2 and NdMn0.88Sb2 show metallic behavior. Negative magnetoresistance in LaMn0.91Sb2 and NdMn0.88Sb2 are possibly related to canted-antiferromagnetic orders of Mn sublattices.