Anomalous Hall effect and rich magnetic phase diagram of Mn 100 − x Rh x epitaxial films

A series of Mn₁₀₀₋ₓRhₓ (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 Mn₁₀₀₋ₓRhₓ 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 $x < 40$, Mn₁₀₀₋ₓRhₓ films undergo a ferromagnetic (FM) transition below TC ≈ 330-350 K; for 40 ≤ x ≤ 45, in addition to the FM transition at TC ≈ 200 K, Mn₁₀₀₋ₓRhₓ films undergo a FM-to-antiferromagnetic (AFM) transition at TN ≈ 120 K; finally for $x > 45$, only one AFM transition at TN ≈ 150 K can be tracked. All the Mn₁₀₀₋ₓRhₓ 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 Mn₁₀₀₋ₓRhₓ films, which become most evident for x = 35. Our systematic investigations suggest a strong correlation between magnetic properties and electronic band topology in Mn₁₀₀₋ₓRhₓ films, highlighting their great potential for AFM spintronics.