Sm-doped Pb(Mg_1/3Nb_2/3)O₃–PbTiO₃ (Sm-PMN–PT) bulk materials have revealed outstanding ferroelectric and piezoelectric properties due to enhanced local structural heterogeneity. In this study, we further explore the potential of Sm-PMN–PT by fabricating epitaxial thin films by pulsed laser deposition, revealing that Sm doping significantly improves the capacitive energy-storage, piezoelectric, electrocaloric, and pyroelectric properties of PMN–PT thin films. These Sm-PMN–PT thin films exhibit fatigue-free performance up to 10⁹ charge–discharge cycles and maintain thermal stability across a wide temperature range from −40 to 200 °C. Notably, the films demonstrate a colossal electrocaloric effect with a temperature change of 59.4 K and a remarkable pyroelectric energy density reaching 40 J cm^–3. By using scanning transmission electron microscopy and phase-field modeling, we revealed that these exceptional properties arise from the increased local structural heterogeneity and strong local electric fields along spontaneous polarization directions, facilitating the nucleation of polymorphic nanodomains characterized by a slush-like polar structure. These findings highlight the enormous potential of Sm-PMN–PT films in capacitive energy storage and solid-state electrothermal energy interconversion. Furthermore, this approach holds broad potential for other relaxor ferroelectrics by enabling the manipulation of nanodomain structures, paving the way for developing robust multifunctional materials.

中文翻译：

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Sm 掺杂 Pb（Mg1/3Nb2/3）O3–PbTiO3 薄膜的热稳定电容能量密度和巨大的电热和热电效应


由于增强的局部结构异质性，Sm 掺杂 Pb（Mg_1/3Nb_2/3）O₃–PbTiO₃ （Sm-PMN–PT） 块状材料显示出出色的铁电和压电性能。在这项研究中，我们通过脉冲激光沉积制备外延薄膜进一步探索了 Sm-PMN-PT 的潜力，揭示了 Sm 掺杂显着改善了 PMN-PT 薄膜的电容储能、压电、电热和热释电性能。这些 Sm-PMN-PT 薄膜在高达 10^{到 9} 次充放电循环中表现出无疲劳性能，并在 -40 至 200 °C 的宽温度范围内保持热稳定性。 值得注意的是，这些薄膜表现出巨大的电热效应，温度变化为 59.4 K，热释电能量密度达到 40 J cm^–3。通过使用扫描透射电子显微镜和相场建模，我们揭示了这些特殊特性源于局部结构异质性的增加和沿自发极化方向的强局部电场，促进了以泥状极性结构为特征的多晶型纳米域的成核。这些发现凸显了 Sm-PMN-PT 薄膜在电容储能和固态电热能互转换方面的巨大潜力。此外，这种方法通过操纵纳米畴结构，为其他弛豫铁电体具有广泛的潜力，为开发强大的多功能材料铺平了道路。