Temperature Dependence of the Intrinsic Anomalous Hall Effect in Nickel

TL;DR

This study reveals that the intrinsic anomalous Hall effect in nickel exhibits a strong temperature dependence, influenced by spin-orbit coupling effects near the Fermi surface, clarifying long-standing confusion about its physical origin.

Contribution

It demonstrates the temperature dependence of the intrinsic AHE in Ni and isolates intrinsic and extrinsic contributions by tuning film resistivity without doping.

Findings

Intrinsic AHE in Ni decreases from 1100 to 500 (ohm*cm)^(-1) with temperature.

Temperature dependence is linked to spin-orbit coupling near the Fermi surface.

Results support the Berry-phase interpretation of the AHE.

Abstract

We investigate the unusual temperature dependence of the anomalous Hall effect in Ni. By varying the thickness of the MBE-grown Ni films, the longitudinal resistivity is uniquely tuned without resorting to doping impurities; consequently, the intrinsic and extrinsic contributions are cleanly separated out. In stark contrast to other ferromagnets such as Fe, the intrinsic contribution in Ni is found to be strongly temperature dependent with a value of 1100 (ohm*cm)^(-1) at low temperatures and 500 (ohm*cm)^(-1) at high temperatures. This pronounced temperature dependence, a cause of long-standing confusion concerning the physical origin of the AHE, is likely due to the small energy level splitting caused by the spin orbit coupling close to the Fermi surface. Our result helps pave the way for the general claim of the Berry-phase interpretation for the AHE.