Observation of orbital two-channel Kondo effect in a ferromagnetic L10-MnGa film

TL;DR

This paper reports the experimental observation of the orbital two-channel Kondo effect in a ferromagnetic L10-MnGa film, demonstrating its robustness and extending its known host materials.

Contribution

It provides the first experimental realization of orbital 2CK effect in a ferromagnetic alloy, showing its stability under magnetic fields and in disordered conductors.

Findings

Resistivity upturn is magnetic field-independent.

Resistivity shows logarithmic and square-root temperature dependence.

Orbital 2CK effect persists in ferromagnetic and disordered materials.

Abstract

The experimental existence and stability of the quantum criticality point of the two-channel Kondo (2CK) effect displaying exotic non-Fermi liquid physics has been buried in persistent confusion despite the intensive theoretical and experimental efforts in past three decades. Here we report an experimental realization of the two-level system scattering-induced orbital 2CK effect in a ferromagnetic L10-MnGa film, which is signified by a magnetic field-independent resistivity upturn that has a logarithmic and square-root temperature dependence beyond and below the Kondo temperature of ~14.5 K, respectively. Our result not only evidences the robust existence of orbital 2CK effect even in the presence of strong magnetic fields and long-range ferromagnetic ordering but also extends the scope of 2CK host materials from nonmagnetic nanoscale point contacts to diffusive conductors of disordered alloys.