Coexistence of unconventional spin Hall effect and antisymmetric planar Hall effect in IrO2

Crystal symmetry plays an important role in the Hall effects. Unconventional spin Hall effect (USHE), characterized by Dresselhaus and out-of-plane spins, has been observed in materials with low crystal symmetry. Recently, antisymmetric planar Hall effect (APHE) was discovered in rutile RuO₂ and IrO₂ (101) thin films, which also exhibit low crystal symmetry. In this study, we report the observation of both USHE and APHE in IrO₂ (111) films, using spin-torque ferromagnetic resonance and harmonic Hall measurements, respectively. Notably, the unconventional spin-torque efficiency from Dresselhaus spin was more than double that of a previous report. Additionally, the temperature dependence of APHE suggests that it arises from the Lorentz force, constrained by crystal symmetry. Symmetry analysis supports the coexistence of USHE and APHE and demonstrates that both originate from the crystal symmetry of IrO₂ (111), paving the way for a deeper understanding of Hall effects and related physical phenomena.