Anisotropic magnetism of polymorphic ErAl₃

This talk presents the physical properties of two ErAl₃ polymorphs—trigonal (α) and cubic (β)—through single crystal measurements. Both polymorphs exhibit antiferromagnetic ordering at low temperatures. The β-ErAl₃ polymorph undergoes a transition at T_N = 5.1 K, which is progressively suppressed by the application of an external magnetic field. In contrast, α-ErAl₃ exhibits more complex behavior, with successive transitions at T_N = 5.7 K and T₂ = 4.6 K. When a magnetic field is applied parallel to the c-axis, metamagnetic transitions are observed with magnetization plateaus near one-half of the saturation moment for T < T₂. Corresponding features are also evident in the magnetotransport measurements. The rich H - T phase diagram reveals the complex magnetic behavior of α-ErAl₃, suggesting an important role of competing interactions in this metallic system with three-dimensional character.