Fabrication And Physical Properties Of Flexible Perovskite Manganese Oxide Films

Perovskite-type manganese oxide has many interesting physical properties,such as Jahn-Teller effect,ferroelectricity,non-linear optical characteristics,magnetoelectric coupling caused by double exchange,giant magnetism Resistance effect and so on.Especially in the group II metal-doped thin film system,there are many novel and interesting physical phenomena such as lattice mismatch and anisotropic magnetoresistance effect.With the rapid rise of the Internet of Things in 5G today,and with the rapid development of the microelectronics industry,perovskite manganese oxide films doped with group?metal elements are expected to be widely used in the next generation of new multifunctional devices,such as magnetic sensors,Magnetic memory,etc.Sr-doped LaMnO₃,La_1-xSr_xMnO₃,because of the Curie temperature and metal-insulation transition temperature of Sr-doped LaMnO₃in the single crystal(>0.175)is near room temperature,coupled with good metal conductivity,has been a focus of attention in recent years.Many physical properties of La_1-xSr_xMnO₃ in the bulk state have a complete research system based on many previous reports.With the continuous improvement of film fabrication technology,research on high-quality La_1-xSr_xMnO₃ thin films has also been gradually carried out,but that is mostly limited on rigid films.The advent of the Internet of Things era has made flexibility become a hard requirement for next-generation functional devices,and it is also the direction of development in the field of material physics.In this paper,a high-quality thin film is grown on a flexible substrate fluorine crystal mica by pulse laser deposition technology.And we investigated the magnetic,electrical transport,and optical properties of the flexible LSMO thin film.The specific work is as follows:1.First,we carried out the research of La_0.8Sr_0.2MnO₃.We prepared La_0.8Sr_0.2MnO₃ ceramic target by solid-phase reaction method.Then,a La_0.8Sr_0.2MnO₃ thin film was deposited on a substrate of La Al O₃(001)by pulsed laser deposition.The crystal structure was proved to be epitaxial by XRD.And the surface of the film was flat and uniform by AFM.Obvious ferromagnetic paramagnetic phase transitions were measured in the magnetic test of LSMO thin film.After conducting resistivity-temperature tests on LSMO films with different thicknesses,we fitted them with polaron framework,and proved that polarons also exist in the low-temperature metal region of LSMO films.2.La_0.8S_r0.2MnO₃ thin film was epitaxially grown on the flexible substrate mica.After using XRD and AFM to determine that the film has good epitaxiality and flatness,its magnetic and resistance was tested by SQUID and PPMS,respectively.It was found that the LSMO film on mica still maintained many excellent characteristics found on rigid substrates,such as FM-PM phase transition.After bending the flexible LSMO film sample at high frequency,it is found that the magnetic properties of the film will be slightly improved after bending.3.We epitaxially grown a La_0.7Sr_0.3MnO₃ film on a mica substrate by PLD.The LSMO film was subjected to different bending times and tested for its electrical transport performance.It was found that different degrees of mechanical bending would not change its metal-insulation transition temperature,but would slightly increase the resistance of the LSMO film.Next,we prepared a La_0.7Sr_0.3MnO₃/Sr Ti O₃ film as a comparison,tested the optical transmittance of the two,and found that the optical transmittance of the LSMO film will gradually increase with increasing temperature.