摘要
We investigate the spin Hall magnetoresistance(SMR)in all-antiferromagnetic heterostructuresα-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 theα-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.
基金
supported by the National Key R&D Program of China(Grant No.2021YFB3601301)
the National Natural Science Foundation of China(Grant No.51871130)
the Natural Science Foundation of Beijing Municipality(Grant No.JQ20010)。
