Abstract Crystal structures, dielectric, ferroelectric properties and electrocaloric effects of hetero-valent substituted Ba(Ti 1- x Y x )O 3- x /2 ceramics were studied in the present work. The polar space group of P 4 mm was adopted based on the Rietveld refinement at room temperature. The diffusivity of phase transition and relaxor behavior are both strengthened by the yttrium substitution. The maximal pyroelectric coefficient decreases, and the extent of corresponding temperature deviated from the dielectric peak temperature to higher temperature increases with increasing the yttrium content. The adiabatic temperature changes and isothermal entropy changes display the same tendencies as those of the pyroelectric coefficients. The Ba(Ti 0.944 Y 0.056 )O 2.972 ceramic shows the largest adiabatic temperature change and largest isothermal entropy change among all compositions over a broad temperature range of 50 K. For individual composition, the value of pyroelectric coefficient decreases with increasing the magnitude of applied electric field, and the temperature of maximal pyroelectric coefficient deviates from the dielectric peak temperature to higher temperature. Therefore, the optimal electrocaloric temperature can be adjusted by the magnitude of electric field in relaxor ferroelectricity.

中文翻译：

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弛豫铁电 Ba(Ti 1-x Y x )O 3-x/2 陶瓷在宽温度范围内的电热效应

摘要 本文研究了杂价取代的Ba(Ti 1- x Y x )O 3- x /2 陶瓷的晶体结构、介电、铁电性能和电热效应。基于室温下的 Rietveld 精修采用 P 4 mm 的极空间群。相变的扩散率和弛豫行为都通过钇取代而得到加强。随着钇含量的增加，最大热电系数降低，相应温度从介电峰值温度向更高温度的偏离程度增加。绝热温度变化和等温熵变化显示出与热电系数相同的趋势。Ba(Ti 0.944 Y 0.056 )O 2。972 陶瓷在所有成分中在 50 K 的宽温度范围内表现出最大的绝热温度变化和最大的等温熵变化。对于单个成分，热电系数值随着外加电场强度的增加而减小，最大热电系数的值随着外加电场的增加而减小。系数从介电峰值温度偏离到更高的温度。因此，可以通过弛豫铁电体中电场的大小来调节最佳电热温度。并且最大热电系数的温度从介电峰值温度偏离到更高的温度。因此，可以通过弛豫铁电体中电场的大小来调节最佳电热温度。并且最大热电系数的温度从介电峰值温度偏离到更高的温度。因此，可以通过弛豫铁电体中电场的大小来调节最佳电热温度。