This paper describes two perovskite high entropy oxide (PHEO) compositions: Pb(Hf_0.2Zr_0.2Ti_0.2Nb_0.2Mn_0.2)O₃ (Mn PHEO) and Pb(Hf_0.2Zr_0.2Ti_0.2Nb_0.2Al_0.2)O₃ (Al PHEO). Powders are prepared by conventional solid state sintering by first pre-reacting the B-site oxides, then adding PbO. Phase pure Mn PHEO powder is obtained following calcination of the mixed powders at 750 °C for 240 min; however, secondary phases persisted in Al PHEO for heat treatments from 750 °C to 1200 °C. The Mn PHEO undergoes an entropy-driven phase transformation. Thin films of these compounds are synthesized by pulsed laser deposition (PLD) on a lead zirconate titanate seed layer on Pt-coated SiO₂/Si. The dielectric response of the Mn PHEO films show some contribution from space charge polarizability; in contrast, the Al PHEO films show a slim ferroelectric hysteresis loop and relaxor-like characteristics. The Al PHEO has a dielectric permittivity of ≈2000 with a loss tangent <0.05 from 100 Hz to 100 kHz; it has a dielectric maximum at 105 ± 0.5 °C and a Burns’ temperature of 234 ± 0.5 °C. Indirect measurements based on the Maxwell-relations yielded a maximum electrocaloric temperature change of 8.4 K at 180 °C under the applied electric field of 1186 kV cm⁻¹.

中文翻译：

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钙钛矿高熵氧化物薄膜的电热效应

本文介绍了两种钙钛矿高熵氧化物 (PHEO) 成分：Pb(Hf _0.2 Zr _0.2 Ti _0.2 Nb _0.2 Mn _0.2 )O ₃ (Mn PHEO) 和 Pb(Hf _0.2 Zr _0.2 Ti _0.2 Nb _0.2 Al _0.2 )O ₃（Al PHEO）。通过首先预反应 B 位氧化物，然后添加 PbO，通过常规固态烧结制备粉末。将混合粉末在 750 °C 下煅烧 240 分钟后获得相纯 Mn PHEO 粉末；然而，在 750 °C 至 1200 °C 的热处理过程中，Al PHEO 中仍存在第二相。Mn PHEO 经历了熵驱动的相变。_{这些化合物的薄膜是通过脉冲激光沉积 (PLD) 在铂涂层 SiO 2}上的锆钛酸铅种子层上合成的/硅。Mn PHEO 薄膜的介电响应显示出空间电荷极化率的一些贡献；相比之下，Al PHEO 薄膜显示出细长的铁电磁滞回线和类弛豫特性。Al PHEO 的介电常数约为 2000，在 100 Hz 至 100 kHz 范围内损耗角正切 <0.05；它的介电最大值为 105 ± 0.5 °C，烧伤温度为 234 ± 0.5 °C。基于麦克斯韦关系的间接测量在 1186 kV cm ^-1的施加电场下在 180 °C 下产生了 8.4 K 的最大电热温度变化。