Planar Hall Effect and Magnetoresistance Effect in Pt/Tm3Fe5O12 Bilayers at Low Temperature

Spin transport behaviors in heavy metal/ferromagnetic insulator (HM/FI) bilayers have attracted considerable attention due to various novel phenomena and applications in spintronic devices. Herein, we investigate the planar Hall effect (PHE) in Pt/Tm3Fe5O12 (Pt/TmIG) heterostructures at low temperatures; moment switching in the ferrimagnetic insulator TmIG is detected by using electrical measurements. Double switching hysteresis PHE curves are found in Pt/TmIG bilayers, closely related to the magnetic moment of Tm3+ ions, which makes a key contribution to the total magnetic moment of TmIG film at low temperature. More importantly, a magnetoresistance (MR) curve with double switching is found, which has not been reported in this simple HM/FI bilayer, and the sign of this MR effect is sensitive to the angle between the magnetic field and current directions. Our findings of these effects in this HM/rare earth iron garnet (HM/REIG) bilayer provide insights into tuning the spin transport properties of HM/REIG by changing the rare earth.