Thickness dependent Raman study of epitaxial LaMnO₃ thin films

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• 作者：Aditi Chaturvedi ; Vasant Sathe
• 关键词：Thin films ; Raman spectroscopy ; Jahn&ndash ; Teller distortion
• 刊名：Thin Solid Films
• 出版年：2 December, 2013
• 年：2013
• 卷：548
• 期：Complete
• 页码：75-80
• 全文大小：899 K

文摘

Epitaxial thin films of LaMnO₃ of increasing thickness from 20 nm to 200 nm are deposited on LaAlO₃ (001) substrates by pulsed laser deposition. The films are in-plane compressively strained and a 20 nm film is fully strained. The strain relaxation mechanism in these films is studied by X-ray diffraction and it is observed that the strain relaxes gradually as the thickness is increased. The low temperature Raman measurements on these films revealed that the Jahn-Teller distortion is responsible for the magnetic transition temperature in these films. The Jahn-Teller distortion is found to increase with decreasing film thickness that results in decreasing magnetic transition temperature. The films with thicknesses of 40 and 20 nm showed structural quenching due to strong strain imposed by the substrate.