Intriguing photo-control of exchange bias in BiFeO(3)/La(2/3)Sr(1/3)MnO(3) thin films on SrTiO(3) substrates

To date, electric fields have been widely used to control the magnetic properties of BiFeO(3)-based antiferromagnet/ferromagnet heterostructures through application of an exchange bias. To extend the applicability of exchange bias, however, an alternative mechanism to electric fields is required. Here, we report the photo-control of exchange bias in BiFeO(3)/La(2/3)Sr(1/3)MnO(3) thin films on an SrTiO(3) substrate. Through an ex situ pulsed laser deposition technique, we successfully synthesized epitaxial BiFeO(3)/La(2/3)Sr(1/3)MnO(3) thin films on SrTiO(3) substrates. By measuring magnetoresistance under light illumination, we investigated the effect of light illumination on resistance, exchange bias, and coercive field in BiFeO(3)/La(2/3)Sr(1/3)MnO(3) thin films. After illumination of red and blue lights, the exchange bias was sharply reduced compared to that measured in the dark. With increasing light intensity, the exchange bias under red and blue lights initially decreased to zero and then appeared again. It is possible to reasonably explain these behaviors by considering photo-injection from SrTiO(3) and the photo-conductivity of La(2/3)Sr(1/3)MnO(3). This study may provide a fundamental understanding of the mechanism underlying photo-controlled exchange bias, which is significant for the development of new functional spintronic devices.