摘要
The electrocaloric effect(ECE)is studied in(Pb_(0.8)Ba_(0.2))[(Zn_(1/3)Nb_(2/3))_(0.7)Ti_(0.3)]O_(3) relaxor ferroelectric ceramic by using an“indirect method”.The electric dependence for the polarization(hysteresis loops)has been obtained for several temperatures showing typical relaxor characteristics.The temperature change△T,which is associated with the ECE,is calculated by using the temperature dependence for the polarization.A maximum value for△T is observed for temperatures close above the freezing temperature,showing an indirect evidence of that critical temperature.The results are discussed considering the contribution of the polar nanoregions to the polarization.
基金
The author wishes to thank to the Third World Academy of Sciences(RG/PHYS/LA No.99-050,02-225 and 05-043)for financial support and to ICTP for financial support of LatinAmerican Network of Ferroelectric Materials(NET-43).
