摘要
Ferroelectric thin/thick films with large electrocaloric(EC)effect are critical for solid state cooling technologies.Here,large positive EC effects with two EC peaks in a broad temperature range(~100 K)were obtained in 0.95Pb_(0.92)La_(0.08)(Zr_(0.70)Ti_(0.30))_(0.98)O_(3)-0.05BiFeO_(3)(BFO-La-codoped PZT)epitaxial thin films deposited on the(100),(110)and(111)oriented SrTiO_(3)(STO)substrates by a sol-gel method.The thin film deposited on the(111)oriented STO substrate exhibited a stronger EC effect(~20.6 K at 1956 kV/cm)near room temperature.However,the thin films deposited on the(100)and(110)oriented STO substrates exhibited a stronger EC effect(~18.8 K at 1852 kV/cm and~20.8 K at 1230 kV/cm,respectively)around the peak of the dielectric permittivity(T_(m),~375 K).Particularly,as the direction of the applied electric field was switched(E<0),the DT of the(100)-oriented thin films around T_(m) was enhanced significantly from 18.8 K to 38.1 K.The self-induced-poling during the preparing process maybe plays a key role on the magic phenomenon.It can be concluded that the BFO-La-codoped PZT epitaxial thin films are promising candidates for application in the next solid-state cooling devices.
基金
supported by the National Natural Science Foundation of China(51402196,51973170)
the Innovation Project of Guangxi Graduate Education(YCSW2020047)
the Guangxi Natural Science Foundation(2017GXNSFFA198015)
the open Foundation of Guangxi Key Laboratory of Optical and Electronic Materials and Devices(20KF-6)
the Natural Science Foundation of Shaanxi Province(Grant No.2019JCW-17,2020JCW-15)
the Development and Planning Guide Foundation of Xidian University(Grant No.21103200005).
