Thin films and heterostructures of hexagonal manganites as promising multiferroic materials have attracted a considerable interest. We report structural transformations of high-quality strain-stabilized epitaxial hexagonal ${\mathrm{TbMnO}}_3/\mathrm{yttria}$ stabilized zirconia(111) (h-TMO) films, analyzed by means of various characterization techniques. A reversible structural phase transition from $P{6}_{3}cm$ to $P{6}_3/mmc$ structure at $T_{\mathrm{C}}\sim 800\mathrm{K}$ was observed in stoichiometric h-TMO films by temperature-dependent Raman spectroscopy and optical ellipsometry. The latter, directly probing the electronic system, indicates its modification at the structural phase transition, likely due to charge transfer from oxygen to Mn. A partially reversible phase transformation and stress relaxation was observed in h-TMO films with Tb excess after temperature cycling (300-1000-300 K) during Raman and ellipsometry. An inhomogeneous microstructure, containing ferroelectric and paraelectric nanodomains, was revealed by transmission electron microscopy in the Tb-rich film after annealing. The results obtained indicate a strong influence of stress, induced by temperature and by constrained sample geometry, onto the structure and ferroelectricity of strain-stabilized h-TMO thin films.

中文翻译：

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六角形TbMnO3薄膜的应变驱动结构-铁电关系

作为有前途的多铁性材料，六角锰矿的薄膜和异质结构引起了人们的极大兴趣。我们报告高质量的应变稳定外延六角形的结构转变${\mathrm{三氧化二锰}}_3/\mathrm{氧化钇}$稳定的氧化锆（111）（h-TMO）膜，通过各种表征技术进行了分析。可逆的结构相变$P{6}_{3}C米$ 至 $P{6}_3/米米C$ 结构在 ${Ť}_{\mathrm{C}}〜800\mathrm{ķ}$通过依赖于温度的拉曼光谱和光学椭圆光度法在化学计量的h-TMO薄膜中观察到了α-烯烃。后者直接探测电子系统，表明其在结构相变处的修饰，可能是由于电荷从氧转移到Mn所致。在拉曼光谱和椭偏仪的温度循环（300-1000-300 K）后，在Tb过量的h-TMO薄膜中观察到部分可逆的相变和应力松弛。退火后，由富电子的Tb薄膜通过透射电子显微镜揭示了一个包含铁电和顺电纳米域的不均匀微观结构。获得的结果表明，由温度和受约束的样品几何形状引起的应力对应变稳定的h-TMO薄膜的结构和铁电性有很大影响。