Optical control of magnetism in manganite films

We investigate the optical control of magnetism of $\mathrm{L}{\mathrm{a}}_1/2\mathrm{S}{\mathrm{r}}_1/2\mathrm{Mn}{\mathrm{O}}_{3\ensuremath{-}\ensuremath{\delta}}$ via the manipulation of anisotropic magnetoresistance under the irradiation of a common red-light light-emitting diode. The window of the anisotropic magnetoresistance curve under a sweeping magnetic field is enlarged under the irradiation of red light, indicating an increase of saturation magnetization. The optical control of magnetization is reversible and strongly dependent on the light intensity and the $\mathrm{M}{\mathrm{n}}⁴⁺$ content of $\mathrm{L}{\mathrm{a}}_1/2\mathrm{S}{\mathrm{r}}_1/2\mathrm{Mn}{\mathrm{O}}_{3\ensuremath{-}\ensuremath{\delta}}$. A model of the photon-induced transition of spin electrons is proposed to explain the optical manipulation, according to the half-metallic electronic structure given by first-principles calculations. In addition to the fundamental significance, our findings advance the application of optical manipulation of magnetism in spintronics.