Abstract—

Barium strontium niobate films ~300 nm in thickness have been grown on MgO(001) substrates by rf sputtering of a ceramic target with the stoichiometric composition Sr_0.5Ba_0.5Nb₂O₆ (SBN50) in an oxygen atmosphere. Composition–depth profiles across the films have been measured using secondary ion mass spectrometry, and we have determined their phase composition, structure, and c cell parameter in the temperature range 20–500°C. The results demonstrate that the SBN50 films are heteroepitaxial and have two crystallographic orientations with an angle of ~36.8° between them and identical tetragonal cell parameters (а = 12.438 Å and с = 3.955 Å). Their chemical composition does not vary in the thickness direction and corresponds to the composition of the ceramic target. The SBN50 films have a higher temperature of the ferroelectric-to-paraelectric phase transition than do SBN50 single crystals and polycrystalline films, and their thermal expansion coefficient changes sign near 100°C.

中文翻译：

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20–500°C温度范围内Sr 0.5 Ba 0.5 Nb 2 O 6薄膜的结构特征

摘要-

通过在氧气气氛中用化学计量组成为Sr _0.5 Ba _0.5 Nb ₂ O ₆（SBN50）的陶瓷靶进行rf溅射，在MgO（001）衬底上生长了厚约300 nm的铌酸锶钡薄膜。使用二次离子质谱仪测量了整个膜的成分深度分布图，我们确定了它们在20–500°C温度范围内的相组成，结构和c池参数。结果表明，SBN50薄膜是异质外延的，具有两个晶体学取向，它们之间的夹角约为36.8°，并且具有相同的四方晶胞参数（а = 12.438Å和с= 3.955Å）。它们的化学组成在厚度方向上没有变化，并且对应于陶瓷靶的组成。SBN50薄膜具有比SBN50单晶和多晶薄膜更高的铁电至顺电相变温度，并且它们的热膨胀系数在100°C附近变化明显。