Light-Induced Decoupling of Electronic and Magnetic Properties in Manganites
Henry Navarro, Ali C. Basaran, Fernando Ajejas, Lorenzo Fratino, Soumen Bag, Tianxing Damir Wang, Erbin Qiu, V. Rouco, Isabel Tenreiro, Felipe Torres, A. Rivera, J. Santamarı́a, M. J. Rozenberg, Iván K. Schuller
Abstract
The strongly correlated material ${\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{Mn}\mathrm{O}}_{3}$ ($\mathrm{LSMO}$) exhibits metal-to-insulator and magnetic transition near room temperature. Although the physical properties of $\mathrm{LSMO}$ can be manipulated by strain, chemical doping, temperature, or magnetic field, they often require large external stimuli. To include additional flexibility and tunability, we developed a hybrid optoelectronic heterostructure that uses photocarrier injection from cadmium sulfide ($\mathrm{Cd}\mathrm{S}$) to an $\mathrm{LSMO}$ layer to change its electrical conductivity. $\mathrm{LSMO}$ exhibits no significant optical response; however, the $\mathrm{Cd}\mathrm{S}/\mathrm{LSMO}$ heterostructures show an enhanced conductivity, with a resistance drop of about 37%, at the transition temperature under light stimuli. This enhanced conductivity in response to light is comparable to the effect of a 9 T magnetic field in pure $\mathrm{LSMO}$. Surprisingly, the optical and magnetic responses of $\mathrm{Cd}\mathrm{S}/\mathrm{LSMO}$ heterostructures are decoupled and exhibit different effects when both stimuli are applied. This unexpected behavior shows that heterostructuring strongly correlated oxides may require a new understanding of the coupling of physical properties across the transitions and provide the means to implement new functionalities.