The Effect Of Strain On ABO₃ Type Perovskite Oxides

The transition metal oxide of ABO₃ type perovskite is a strongly correlated electron system with rich physical properties,which provides a broad stage for the research in the field of condensed matter physics,spintronics,etc.The key of designing and developing the oxide electronic devices and new energy materials that meet different performance requirements is in-depth study of microstructure,electronic structure and physical mechanism of the ABO₃ perovskite system.The object of this paper's research mainly contains two typical strongly correlated electron systems,which are 3d transition metal oxide La_2/3Ca_1/3Mn O₃ and 4d transition metal oxide SrRuO₃related systems.By changing the substrate type and film thickness to control the stress of La_2/3Ca_1/3Mn O₃,and through 5d transition metal,Ir,doping with SrRuO₃.The design and adjustment of the crystal structure and electronic structure of the ABO₃ type perovskite system material are realized,and got the following achievements:1.La_2/3Ca_1/3Mn O₃ high-quality epitaxial thin films grown on Sr Ti O₃ and La Al O₃?001?under the effect of tensile/compressive strain respectively,the former one has greater surface roughness,stronger electron localization,and lower magnetic transition temperature,and additional Raman mode;La_2/3Ca_1/3Mn O₃ thin films of different thickness are deposited and grown on La Sr Al O₃substrate.The thin film has a delamination phenomenon.The thinner the film,the stronger the localization of electrons.The uneven strain field induces phase separation.As the number of magnetic clusters increases,the magnetic transition temperature decreases.And as the thickness increases,the film strain gradually relaxes.2.There is a mixed valence state of Ru⁵⁺/Ru⁴⁺and Ir⁵⁺/Ir⁴⁺in SrRuO₃ system doped with 5d transition metal Ir.With the increase of Ir doping content,the ferromagnetic order decreases,and the spin glass state behavior occurs in low temperature.And the exchange bias effect appears at the interface between ferromagnetic and antiferromagnetic.In addition,the application of synchrotron radiation technology in the interface electronic system of SrRuO₃ oxide was also studied.The research on the strain regulation in the transition metal oxides of ABO₃ type perovskite structure has laid the foundation for further in-depth understanding,analysis,expansion and regulation of the structure and electromagnetic properties in the oxide electronic system.