Optically switched magnetism in photovoltaic perovskite   CH$_3$NH$_3$(Mn:Pb)I$_3$
  The demand for ever-increasing density of information storage and speed of manipulation boosts an intense search for new magnetic materials and novel ways of controlling the magnetic bit. Here, we report the synthesis of a ferromagnetic photovoltaic CH$_3$NH$_3$(Mn:Pb)I$_3$ material in which the photo-excited electrons rapidly melt the local magnetic order through the Ruderman-Kittel-Kasuya-Yosida interactions without heating up the spin system. Our finding offers an alternative, very simple and efficient way of optical spin control, and opens an avenue for applications in low power, light controlling magnetic devices. 
B. N\'afr\'adi, P. Szirmai, M. Spina, H. Lee, O. V. Yazyev, A.   Arakcheeva, D. Chernyshov, M. Gibert, L. Forr\'o and E. Hor...
cond-mat.mtrl-sci