Orbital two-channel Kondo effect in epitaxial ferromagnetic L10-MnAl films

TL;DR

This paper reports the first experimental observation of the orbital two-channel Kondo effect in epitaxial L10-MnAl films, demonstrating robust quantum behavior in a ferromagnetic material with strong coupling and magnetic anisotropy.

Contribution

It provides the first experimental realization of the orbital 2CK effect in epitaxial ferromagnetic films, showing enhanced Kondo temperature and robustness against ferromagnetic order.

Findings

Observation of resistivity upturn with lnT and T1/2 dependence

Enhanced Kondo temperature and energy splitting compared to other systems

Orbital 2CK effect persists despite ferromagnetic ordering

Abstract

We report the first experimental realization of orbital two-channel Kondo (2CK) effect from two-level systems (TLSs) in epitaxial L10-MnAl films with giant perpendicular magnetic anisotropy. The resistivity exhibits a low-temperature (T) upturn with a clear transition from a lnT-dependence to T1/2-dependence and deviation from it in three distinct T regimes, which are independent of applied magnetic fields. The magnitudes of Kondo temperature and energy splitting of the TLSs are greatly enhanced in comparison to those in other systems exhibiting orbital 2CK, suggesting strong coupling between the tunneling centers with conduction electrons via resonant scattering. These results point to a considerable robustness of the orbital 2CK effect even in the presence of ferromagnetic ordering and significant spin polarization of the conduction electrons.