Suppression of anomalous Hall effect by heavy-fermion in epitaxial antiperovskite Mn_(4-x)Gd_xN films

摘要

Mn4-xGdxN films with x ranging from 0 to 0.48 have been grown by a plasma-assisted molecular beam epitaxy (PA-MBE) system. Analyses show that there is a competition between Kondo coupling and the Ruderman-Kittel-Kasuya-Yosida interaction in these films. The anomalous Hall effect (AHE) was investigated, and a multiple competing scattering mechanism was used to differentiate different contributions to the AHE. Fitting results using a multivariable scaling relation show that contribution of the skew-scattering mechanism to the AHE is suppressed and competition between different contributions is stronger in highly doped samples than that in undoped samples. Resistivity-temperature (rho-T) curves in Gd-rich samples exhibit a typical behavior of heavy fermion (HF) materials. It shows a weak metal conducting behavior in a high temperature range, while Kondo coupling dominates the middle temperature range of 50 K-110 K. With a further decrease in the temperature to 5 K, a Fermi-liquid behavior is found in the range of 5 K-20 K. Comprehensive analyses indicate that Mn4-xGdxN with large x might be a new kind of HF material with room temperature ferromagnetism. Published by AIP Publishing.