Anomalous Hall effect in L 1 0 − MnAl films with controllable orbital two-channel Kondo effect

The anomalous Hall effect (AHE) in strongly disordered magnetic systems has been buried in persistent confusion despite its long history. We report the AHE in perpendicularly magnetized $L{1}_{0}\text{\ensuremath{-}}\mathrm{MnAl}$ epitaxial films with a variable orbital two-channel Kondo (2CK) effect arising from the strong coupling of conduction electrons and the structural disorders of two-level systems. The AHE is observed to excellently scale with ${\ensuremath{\rho}}_{\mathrm{AH}}/f={a}_{0}{\ensuremath{\rho}}_{xx0}+b{\ensuremath{\rho}}_{xx}^{2}$ at high temperatures where phonon scattering prevails. In contrast, significant deviation occurs at low temperatures where the orbital 2CK effect becomes important, suggesting a negative AHE contribution. The deviation of the scaling agrees with the orbital 2CK effect in the breakdown temperatures and deviation magnitudes.