Magnetic Field Effect on Magnetic and Electrical Properties of ${\hbox {Mn}}_{2\hbox {-}{\rm x}}{\hbox {Cu}}_{\rm x}{\hbox {Sb}}$

In order to investigate the magnetic and the electrical properties of Mn_2-xCu_xSb (x =0.06, 0.10, and 0.15), the magnetization and the electrical resistivity measurements were carried out in the temperature range from 10 K to 300 K under magnetic fields up to μ₀ H=5 T. The Curie temperature T_C of Mn_1.94Cu_0.06Sb was determined to be 517 K. Mn_1.94Cu_0.06Sb showed a first-order magnetic transition from a ferrimagnetic (FRI) to an antiferromagnetic (AFM) phase at T_t = 117 K with a thermal hysteresis of approximately 20 K. The low-field magnetic data of Mn_1.94Cu_0.06Sb also showed an anomaly at 207 K, indicating a spin reorientation. With increasing x, T_t increases to 154 K (x = 0.15), whereas T_C is almost constant for 0.06 ≤ x ≤ 0.15. The electrical resistivity changes abruptly by 25%-36% at T_t. By applying a magnetic field of μ₀ H=5 T, T_t decreases and the width of the hysteresis increases. In addition, we confirmed that the value of the magnetization at low temperatures below Tt depends on the cooling process for a magnetic field.