Tunable Spin Hall Magnetoresistance in All-Antiferromagnetic Heterostructures

• Published in: Chinese physics letters 2022-04, Vol.39 (4), p.47502-107
• Main Authors: Huang, Lin, Zhou, Yongjian, Guo, Tingwen, Pan, Feng, Song, Cheng
• Format: Article
• Language: English
• ISSN: 0256-307X; 1741-3540
• DOI: 10.1088/0256-307X/39/4/047502

We investigate the spin Hall magnetoresistance (SMR) in all-antiferromagnetic heterostructures α -Fe 2 O 3 /Cr 2 O 3 with Pt contacts. When the temperature is ultralow (< 50 K), the spin current generated in the Pt layer cannot be transmitted through Cr 2 O 3 ( t = 4 nm), and the SMR is near zero. Meanwhile, when the temperature is higher than the spin fluctuation temperature T F (≈ 50 K) of Cr 2 O 3 and lower than its Néel temperature T N (≈ 300 K), the spin current goes through the Cr 2 O 3 layer and is reflected at the α -Fe 2 O 3 /Cr 2 O 3 interface; an antiferromagnetic (negative) SMR is observed. As temperature increases higher than T N , paramagnetic (positive) SMR mainly arises from the spin current reflection at the Cr 2 O 3 /Pt interface. The transition temperatures from negative to positive SMR are enhanced with increasing Cr 2 O 3 layer thickness, accompanied by the absence of SMR signals when t = 10 nm. Such a tunable SMR builds a bridge between spin transport and structures. It also enriches antiferromagnetic spintronics.