Effects of thermal annealing on the spin–orbit torque and unidirectional spin Hall magnetoresistance in Pt/CoFe/Ta trilayers
Guonan Feng,
Di Fu,
Xi Chen,
Jintao Liu,
Xinyan Yang,
Xiaorong Liang,
Penghao Lv,
Di Zhao,
Minggao Zuo,
Guanghua Yu
Affiliations
Guonan Feng
Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083, China
Di Fu
MIIT Key Laboratory of Advanced Display Materials and Devices, School of Materials Science and Engineering, Institute of Optoelectronics and Nanomaterials, Nanjing University of Science and Technology, Nanjing 210094, China
Xi Chen
MIIT Key Laboratory of Advanced Display Materials and Devices, School of Materials Science and Engineering, Institute of Optoelectronics and Nanomaterials, Nanjing University of Science and Technology, Nanjing 210094, China
Jintao Liu
Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083, China
Xinyan Yang
Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083, China
Xiaorong Liang
MIIT Key Laboratory of Advanced Display Materials and Devices, School of Materials Science and Engineering, Institute of Optoelectronics and Nanomaterials, Nanjing University of Science and Technology, Nanjing 210094, China
Penghao Lv
MIIT Key Laboratory of Advanced Display Materials and Devices, School of Materials Science and Engineering, Institute of Optoelectronics and Nanomaterials, Nanjing University of Science and Technology, Nanjing 210094, China
Di Zhao
Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083, China
Minggao Zuo
Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083, China
Guanghua Yu
Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083, China
We investigated the spin–orbit torque (SOT) and unidirectional spin Hall magnetoresistance (USMR) in Pt/CoFe/Ta trilayer as well as Pt/CoFe and CoFe/Ta bilayers with in-plane magnetic anisotropy by performing transverse and longitudinal second harmonic resistance measurements. Compared to the two bilayers, we found that the trilayer exhibits enhanced SOT and USMR due to the opposite spin Hall angles of Pt and Ta, which work together to enhance the spin accumulation in the trilayer. Furthermore, we found that thermal annealing has a significant influence on the magnitude and sign of the SOT and USMR in the Pt/CoFe/Ta trilayers. Specifically, we observed that both the damping-like SOT and USMR of the trilayer decrease as the annealing temperature increases, and they even change signs at an annealing temperature between 235 and 265 °C. In contrast, the sign change of the SOT and USMR upon annealing is absent in the Pt/CoFe and CoFe/Ta bilayers. These findings suggest that the sign of the SOT and USMR in the Pt/CoFe/Ta trilayer can be easily manipulated by using an appropriate thermal annealing treatment, which has important implications for the development of novel spintronic devices.
