P. Marsik, R. de Andrés Prada, Andreana Daniil, C. Bernhard
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引用次数: 0
Abstract
Abstract We performed infrared and time-domain terahertz spectroscopic ellipsometry measurements of thin films of the perovskite antiferromagnetic insulator SrMnO3 that were grown by pulsed laser deposition (PLD) on LaAlO3, SrLaGaO4, and LSAT substrates which yield an epitaxial strain ranging from −0.3 to 1.7%. Taking these thin films as a representative example, we discuss the strategies for analyzing the ellipsometry spectra and extracting the information about the thin film dielectric response that can be equally applied to a variety of oxide based thin films and heterostructures. In particular, for the room temperature spectra we show that the three infrared-active phonon modes of the cubic perovskite structure of SrMnO3 undergo the expected softening with increasing tensile strain. For the SrMnO3 film on SrLaGaO4, we find that the low-energy (TO1) phonon mode reveals anomalous temperature dependence in the vicinity of the Néel temperature of about 170 K that signifies a strong spin-phonon coupling. For the SrMnO3 film on LSAT, we identify some irreversible changes of the infrared ellipsometry spectra that occur as the sample is heated to elevated temperature up to 560 K. These changes of the ellipsometry spectra have been attributed to a partial oxygen loss of the SrMnO3 thin film since they can be reverted with a post annealing treatment under high oxygen pressure.
期刊介绍:
Advanced Optical Technologies is a strictly peer-reviewed scientific journal. The major aim of Advanced Optical Technologies is to publish recent progress in the fields of optical design, optical engineering, and optical manufacturing. Advanced Optical Technologies has a main focus on applied research and addresses scientists as well as experts in industrial research and development. Advanced Optical Technologies partners with the European Optical Society (EOS). All its 4.500+ members have free online access to the journal through their EOS member account. Topics: Optical design, Lithography, Opto-mechanical engineering, Illumination and lighting technology, Precision fabrication, Image sensor devices, Optical materials (polymer based, inorganic, crystalline/amorphous), Optical instruments in life science (biology, medicine, laboratories), Optical metrology, Optics in aerospace/defense, Simulation, interdisciplinary, Optics for astronomy, Standards, Consumer optics, Optical coatings.