Manipulation of magnetic and magneto-transport properties of amorphous CoO1–v films

•Magnetic and magneto-transport properties of amorphous CoO1−v are studied.•A giant exchange bias effect with HE≈4380 Oe and HC≈8500 Oe is observed at 5 K.•A metal–insulator transition is observed in CoO1−v by changing the oxygen pressure.•The exchange bias decreases while saturation magnetization increases with annealing.

The magnetic and magneto-transport properties of amorphous CoO1−v films have been systematically studied and manipulated by changing the concentration of oxygen vacancies. A giant exchange bias field HE≈4380 Oe and a large coercivity HC≈8500 Oe are observed at 5 K for the composite films. And, a metal to insulator transition has been demonstrated in CoO1−v films by decreasing the concentration of oxygen vacancies. Moreover, a remarkable decrease of the exchange bias and a slight increase of the saturation magnetization can be obtained by modifying the microstructures through post-thermal annealing.