Novel behaviors of anomalous Hall effect in TbFeCo ferrimagnetic thin films

Abstract

We investigate the temperature dependence and the thickness dependence of anomalous Hall effect (AHE) of TbFeCo ultra-thin films under high magnetic field. The sign change on temperature dependence of AHE in 20nm-thick TbFeCo film with rare-earth (RE) rich composition was observed. The AHE sign at low temperature is negative while it gradually becomes positive as the temperature increases. Moreover, the AHE sign for 5nm-thick TbFeCo film remains positive while that for 50nm-thick TbFeCo film remains negative at temperature in the range from 5 K to 400 K. The similar thickness dependence of AHE in TM-rich samples was also observed. From the mean-field approximation, the sign change temperature in AHE is related to the compensation temperature and the existence of interfacial region, which has the TM-rich composition and the weak anisotropy. Therefore, We clarified that the novel behavior of AHE sign changes in TbFeCo thin films with different thickness can be explained by the interfacial layer with weak anisotropy and two phase model.

Underlying Mechanisms and Tunability of the Anomalous Hall Effect in NiCo2O4 Films with Robust Perpendicular Magnetic Anisotropy

“…In contrast, films grown at elevated temperatures (350 and 375 °C) exhibit an AHE sign reversal between 50 and 150 K, a phenomenon that is rarely reported in single phase materials. [ 38 , 39 , 40 , 41 ] In the case of NCO, a sign reversal has previously been observed only for very thin films with a finite‐size effect being mentioned as its origin. [ 14 , 42 ] However, our work reveals the crucial influence of the NCO conductivity σ xx on the AHE sign reversal (see inset of Figure 4c ) with a negligible influence of the film thickness.…”

Sense current dependent coercivity and magnetization relaxation in Gd-Fe-Co Hall bar

“…At compensation, with vanishing MS, their magnetization dynamics is as fast as antiferromagnet, yet can be sensed by the Hall measurements through the TM sublattices' delectrons [5,10,[21][22][23][24][25]. For spintronics application purposes a basic device consists of the Hall bar pattern, which can be used for anomalous Hall effect (AHE), spin Hall switching, spin torques, domain wall velocity, etc., important characteristics [6,26,27]. In the Hall bar device, the effect of sense current on anomalous Hall effect resistivity, coercivity, domain wall propagation, are key factors for the memory and other spintronics applications [28,29].…”