Anomalous Hall effect and rich magnetic phase diagram of Mn_100−xRh_x epitaxial films

A series of Mn_100−xRh_x (20 ≼ x ≼ 50) thin films were epitaxially grown on the MgO substrate using magnetron sputtering technique, and were systematically investigated by magnetization, longitudinal electrical resistivity, and transverse Hall resistivity. After optimizing the growth conditions, phase-pure Mn_100−xRh_x films with a cubic CsCl-type structure were obtained, and their magnetic phase diagram was built. The manipulation of Rh content leads to a rich magnetic phase diagram, where three different regimes can be identified: for x < 40, Mn_100−xRh_x films undergo a ferromagnetic (FM) transition below T_C ≈ 330–350 K; for 40 ≼ x ≼ 45, in addition to the FM transition at T_C ≈ 200 K, Mn_100−xRh_x films undergo a FM-to-antiferromagnetic (AFM) transition at T_N ≈ 120 K; finally for x > 45, only one AFM transition at T_N ≈ 150 K can be tracked. All the Mn_100−xRh_x films exhibit distinct anomalous Hall effect in their magnetically ordered state, which is most likely due to the intrinsic Berry-curvature mechanism. In addition, all the anomalous Hall transport properties, including the resistivity, conductivity, and angle exhibit a strong correlation with the magnetic properties of Mn_100−xRh_x films, which become most evident for x = 35. Our systematic investigations suggest a strong correlation between magnetic properties and electronic band topology in Mn_100−xRh_x films, highlighting their great potential for AFM spintronics.