Field-free switching of Tm3Fe5O12 on miscut garnet substrates with entangled spin Hall magnetoresistance and anomalous Hall resistance

Electrically manipulating the magnetization of ferrimagnetic insulators, without reliance on an external magnetic field, offers potential for the advancement of fast and energy-efficient spintronic devices. In this paper, we report efficient field-free spin-orbit torque switching in the Tm3Fe5O12/Pt heterostructure epitaxially grown on a vicinal Y3(Sc2Ga3)O12 (7 7 10) substrate with its surface having a 10 degrees miscut angle relative to the (111) orientation. The magnetic easy axis is identified to be approximately along the [443] direction, deviating from the film normal by 17 degrees. This magnetic tilting breaks the in-plane magnetic symmetry and thus leads to the magnetization switching in zero field when the current is applied orthogonal to the miscut direction. Moreover, we observe that the anomalous Hall resistance, typically used to monitor the Tm3Fe5O12 magnetization state, becomes entangled with the transverse effect of the spin Hall magnetoresistance under an in-plane field. The resulting Hall resistance (and even its polarity) in response to the current-induced magnetization switching is significantly modified by the in-plane field. The dynamics of zero-field switching is simulated numerically based on the macrospin model. This work paves the way in the development of spintronic devices utilizing magnetic insulators.