Light-induced decoupling of electronic and magnetic properties in manganites

© 2023 American Physical Society The synthesis of the heterostructures and measurement of transport, magnetic, and optical properties were supported by the U.S. Department of Energy's Office of Basic Energy Science, under Grant DE-FG02-87ER45332, the synthesis of LSMO by the Spanish MCI through Grants No. MAT 2017-87134-C02 and No. PCI 2020-112093, and theory by the French ANR "MoMA" project ANR-19-CE30-0020, Chilean FONDECYT 1211902, and Basal AFB220001.
The strongly correlated material La_0.7Sr_0.3MnO_3 (LSMO) exhibits metal-to-insulator and magnetic tran-sition near room temperature. Although the physical properties of LSMO can be manipulated by strain, chemical doping, temperature, or magnetic field, they often require large external stimuli. To include addi-tional flexibility and tunability, we developed a hybrid optoelectronic heterostructure that uses photocarrier injection from cadmium sulfide (CdS) to an LSMO layer to change its electrical conductivity. LSMO exhibits no significant optical response; however, the CdS/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 LSMO. Surprisingly, the optical and magnetic responses of CdS/LSMO heterostructures are decoupled and exhibit different effects when both stimuli are applied. This unexpected behavior shows that het-erostructuring 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.
U.S. Department of Energy's Office of Basic Energy Science
Ministerio de Ciencia e Innovación (MICINN)
Agence nationale de la recherche (ANR)
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)
Depto. de Física de Materiales
Fac. de Ciencias Físicas
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