Preparation Of Ag - Doped LSMO And Study On LIV Effect

Strongly correlated oxide material La2/3Sr1/3MnO3(LSMO) has great application potential in light detector and magnetic electronic devices owning to its novel effects such as colossal magneto resistance (CMR) effect and laser-induced voltage (LIV) effects.In the experiment, LIV effects of La2/3Sr1/3MnO3:Agx (LSMO:Agx, x is mole%of Ag, x=0.00,0.02,0.04,0.02,0.08,0.10,0.20,0.30,0.40) are systematically studied. LSMO:Agx power was synthesized by chemical co-precipitation method. The polycrystalline composite targets were prepared by solid phase sintering method. Then LSMO:Agx thin films were prepared by pulsed laser deposition (PLD) technique on LaAlO3single crystal substrate. Structure and physical properties of LSMO:Agx composites and films were investigated by X ray diffraction (XRD), resistance versus temperature (R-T) curves, scanning electron microscopy (SEM), atomic force microscope (AFM) and so on. At the same time, We also studied the LIV signal of LSMO:Agx films with different Ag doping level in different deposition process. The experiment results were given as the following:1. Using chemical co-precipitation and solid phase sintering method, we prepared the orthorhombic crystalline perovskite LSMO:Agx powder and polycrystalline composite targets. In the materials, the mole%of Ag element is low, which is associated with the volatilization of Ag at high sintering temperature. D50size of LSMO:Agx powder decreases with the increase of Ag doping, suggesting that Ag doping is advantageous to the grain refinement of LSMO:Agx powder. Ag doping can also effectively improve the electrical properties of LSMO polycrystalline. At x=03, the TCR and Z value both reach to the maximum.2. We prepared LSMO films on LaAlO3single crystal substrate (0°) by PLD technique and studied the influence of different growth condition on the properties of LSMO films by the analysis of XRD and R-T. We obtained the optimum process parameters for preparing LSMO films:growth temperature is790℃, growth oxygen pressure is45pa, and annealing temperature is760℃;3. Using PLD technique, LSMO:Agx thin films were prepared on LaA1O3single crystal substrate (15°). Effects of growth conditions on structure, electrical transport properties and laser-induced voltage (LIV) effect were studied. Under the optimized deposition conditions, the LSMO:Ago.o8thin films have the best crystallization quality, appropriate migration energy and oxygen content. At the same time, Up, Fm and AS were maximum. The long range cooperative Jahn-Teller distortions in the thin films cause the increase of AS and it is the main reason for the enhancement of LIV signal.