Giant Electrocaloric Effect of Oriented Pb(Zr0.95Ti0.05)O3 Ferroelectric Thin Films

Giant Electrocaloric Effect of Oriented Pb(Zr0.95Ti0.05)O3 Ferroelectric Thin Films
　　To remit environment problem, late-model no-Freon (Zr-rich PZT Electro-caloric material) was investigated and prepared. Oriented Pb(Zr0.95Ti0.05)O3 (PZT) thin films with rare earth–La3+ dopants were prepared on Pt/Ti/SiO2/Si substrate by sol-gel technique. Effects of different Thermal treatment methodology on orientation of PZT thin films and different Block neodymium magnet orientation on Electrocaloric of PZT thin films were investigated systematically.Mechanism of oriented growth of Zr-rich PZT thin films was analyzed. Relevant theoretics of oriented growth of Zr-rich PZT thin films was put forward. Different anneal technics and cycstallographic texture of Zr-rich PZT thin films were compared. (100)-oriented Zr-rich PZT thin films was gained by anneal at 650℃for 5min, and (100)-oriented Zr-rich PZT thin films was gained by anneal at 600℃for 3min.
　　Otherwise along with increase of pyrolyzing temperature, (100)-orientation of Zr-rich PZT thin films increase and peaked at 425℃.Based on the analysis of SEM and AFM, an obvious difference in crystallization of PZT thin films with La doping was observed. There was no obvious diffusion and the combine between Pt electrode and PZT thin films and grains with small size and uniform distribution are shown in PZT with 0.5 mol% La3+ dopant. More La3+ dopant was, more large grain was and small degree of coarseness was.Electrocaloric effects of different oriented PZT and PLZT thin films were investigated systematically. It was shown that Electrocaloric of http://www.chinamagnets.biz/ Oriented Zr-rich PZT thin films excelled polycrystalline PZT thin films. max of ElectrocaloricΔT of Oriented Zr-rich PZT thin films was 29K, while max of ElectrocaloricΔT of polycrystalline Zr-rich PZT thin films was 12K. It was also shown that electrocaloric of (111)-oriented Zr-rich PLZT thin films excelled (100)-oriented Zr-rich PZT thin films. La dopant enhanced Electrocaloric of Zr-rich PZT thin films. Rare earth Yb mainly occupied A-site in PZT lattice, the rank of long-range order of ferroelectric structure. Thereby stabilization of ferroelectric structure was restrained, because substitution of La3+ was the no-equivalence electric charge substitution, charge balance of cycstallographic texture was destroied and stabilization of antiferroelectric structure. All of these were prone to increase dispersion of electric field and enforce electrocaloric effects of Zr-rich PZT thin films.