Manipulation of perpendicular exchange bias and spin-orbit torques via MgO in Pt/Co/MgO films

•Strong PEB is obtained in the Pt/Co/MgO film.•The blocking temperature of the Pt/Co/MgO film is higher than that of the Pt/Co/CoO film.•MgO thickness has significant effect on the SOT generation. We study the perpendicular exchange bias (PEB) and spin-orbit torque (SOT) generation in the Pt/Co/MgO heterostructure by changing the thickness of the MgO layer. We show that the oxidation of the beneath Co layer increases with the MgO thickness. Strong PEB is obtained in the Pt/Co/MgO films, which exhibits a much higher blocking temperature compared with that in the Pt/Co/CoO films. Furthermore, it is found that the MgO thickness has significant effect on the SOT generation. Maximum values of the SOTs are obtained with a 0.8 nm-thick MgO layer, which decreases by increasing the MgO thickness from 0.8 to 1.6 nm. Our results shed a light on the essential role of the MgO layer in the heavy metal/ferromagnet/MgO heterostructure, a typical material system in spintronic devices, and provide a way to manipulate the magnetic properties and the SOTs by oxide layers.