Room-temperature ferromagnetism in the Co-doped Ba0.5Sr0.5TiO3 thin films

The authors report the room-temperature ferromagnetism in the epitaxial thin films of 3% Co-doped Ba0.5Sr0.5TiO3 (CBSTO) grown by pulsed laser deposition. These films show the single phase character with Co dopants in the +2 state. More interestingly, ferromagnetic and ferroelectric transitions were observed at 570 and 150K, respectively. The CBSTO films also show the exchange bias effect manifested by the negative shift and training effect of the hysteresis loops at 5K. This work demonstrates that ferromagnetism can be induced in the ferroelectric materials, which is significant for shedding light on the mechanism of dopant induced ferromagnetism in insulators and applications.