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Lei Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Investigation of spin-phonon coupling in triangular-lattice antiferromagnet AgCrS2 by Infrared Transmission Spectroscopy
    Journal of Magnetism and Magnetic Materials, 2016
    Co-Authors: Wenshuai Gao, Youming Zou, Shile Zhang, Liran Shi, Zhengcai Xia, Zhongwen Ouyang, Bingjie Liu, Lei Zhang
    Abstract:

    Abstract In this work, we have investigated the spin-phonon coupling in the triangular-lattice antiferromagnet AgCrS 2 by means of Infrared Transmission Spectroscopy. At 300 K, four IR active phonon modes having the typical profile expected for an insulating material have been observed. These phonon modes are found to continuously harden upon cooling due to the slight shrinkage of the lattice. The splitting of a phonon mode and the occurrence of two new phonon modes are observed at T N , providing evidences for strong spin-phonon coupling. It is noted that phonon eigenfrequencies show significant deviations from the anharmonic contribution at temperatures much higher than T N , which is clearly determined by the strong spin fluctuations. Our results suggest that spin-phonon coupling has strong influence even in PM state in this material.

  • Spin-phonon coupling probed by Infrared Transmission Spectroscopy in the double perovskite Ba2YMoO6
    Journal of Applied Physics, 2013
    Co-Authors: Youming Zou, Shile Zhang, Lei Zhang, Langsheng Ling, Yuheng Zhang
    Abstract:

    In this work, we report a study on the Infrared Transmission Spectroscopy of the double perovskite Ba2YMoO6. At 300 K, three bands are observed at ∼255.1 cm−1, ∼343.4 cm−1, and ∼561.5 cm−1, which are related to the motion between the cation Ba2+ and the anion YMO6−2, the Y-O stretching motion, and the stretching vibration of the MoO6 octahedron, respectively. These modes continue to harden upon cooling owing to the shrink of the lattice constant. When the temperature decreases to T≤130 K around which the spin singlet dimer begins to form, an additional phonon mode appears at ∼611 cm−1, suggesting the occurrence of local distortion of MoO6 octahedra. With further decrease of the temperature, its intensity enhances and its peak position keeps unchanged. These results indicate that the formation of the spin singlet dimers is accompanied with the occurrence of the local structure distortion of MoO6 octahedra, providing evidence for the strong spin-phonon coupling in the double perovskite Ba2YMoO6.

Peter Hess - One of the best experts on this subject based on the ideXlab platform.

  • In situ detection of F2 laser-induced oxidation on hydrogen-terminated Si(111) and Si(110) surfaces by Fourier transform Infrared Transmission Spectroscopy
    Thin Solid Films, 2001
    Co-Authors: J Lambers, Peter Hess
    Abstract:

    Although oxidation of silicon has been intensively investigated experimentally and theoretically, the composition and structure of the interface region between the bulk oxide and silicon are not very well known. In this work, we report on the vacuum UV laser-induced oxidation of well-defined atomically flat Si(111)-(1×1):H and Si(110)-(1×1):H surfaces, prepared by wet-chemical processing, using an F2 laser (157 nm). The silicon samples were irradiated under ultra high vacuum conditions in water and oxygen atmospheres. The photo-induced partial oxidation of the first monolayer, controlled by the oxidant pressure, was monitored by in situ Fourier transform Infrared Transmission Spectroscopy with different photon detectors. The chemical reactions occurring at the surface were monitored by the shift and decreasing strength of the stretching vibration of SiH surface bonds. The IR absorption spectra recorded during surface processing yield detailed information on the rearrangement of chemical bonds with a sensitivity reaching monolayer resolution.

  • In situ Infrared Transmission Spectroscopy of nucleation and growth of amorphous hydrogenated silicon
    Applied Physics Letters, 1996
    Co-Authors: Jürgen Knobloch, Peter Hess
    Abstract:

    We present a series of IR Transmission spectra with submonolayer resolution of the initial growth of amorphous hydrogenated silicon (a‐Si:H) deposited by F2 laser (157 nm) chemical vapor deposition. The film thickness was measured simultaneously using a quartz crystal microbalance with appropriate sensitivity. The presented technique allows the evolution of the H content and bonding configuration on a silicon substrate to be monitored during nucleation and growth. It provides a comparable or even higher sensitivity than that achieved by reflection absorption Spectroscopy using metal surfaces or methods applying multilayer ‘‘optical cavity’’ structures to enhance the IR absorption.

Youming Zou - One of the best experts on this subject based on the ideXlab platform.

  • Investigation of spin-phonon coupling in triangular-lattice antiferromagnet AgCrS2 by Infrared Transmission Spectroscopy
    Journal of Magnetism and Magnetic Materials, 2016
    Co-Authors: Wenshuai Gao, Youming Zou, Shile Zhang, Liran Shi, Zhengcai Xia, Zhongwen Ouyang, Bingjie Liu, Lei Zhang
    Abstract:

    Abstract In this work, we have investigated the spin-phonon coupling in the triangular-lattice antiferromagnet AgCrS 2 by means of Infrared Transmission Spectroscopy. At 300 K, four IR active phonon modes having the typical profile expected for an insulating material have been observed. These phonon modes are found to continuously harden upon cooling due to the slight shrinkage of the lattice. The splitting of a phonon mode and the occurrence of two new phonon modes are observed at T N , providing evidences for strong spin-phonon coupling. It is noted that phonon eigenfrequencies show significant deviations from the anharmonic contribution at temperatures much higher than T N , which is clearly determined by the strong spin fluctuations. Our results suggest that spin-phonon coupling has strong influence even in PM state in this material.

  • Spin-phonon coupling probed by Infrared Transmission Spectroscopy in the double perovskite Ba2YMoO6
    Journal of Applied Physics, 2013
    Co-Authors: Youming Zou, Shile Zhang, Lei Zhang, Langsheng Ling, Yuheng Zhang
    Abstract:

    In this work, we report a study on the Infrared Transmission Spectroscopy of the double perovskite Ba2YMoO6. At 300 K, three bands are observed at ∼255.1 cm−1, ∼343.4 cm−1, and ∼561.5 cm−1, which are related to the motion between the cation Ba2+ and the anion YMO6−2, the Y-O stretching motion, and the stretching vibration of the MoO6 octahedron, respectively. These modes continue to harden upon cooling owing to the shrink of the lattice constant. When the temperature decreases to T≤130 K around which the spin singlet dimer begins to form, an additional phonon mode appears at ∼611 cm−1, suggesting the occurrence of local distortion of MoO6 octahedra. With further decrease of the temperature, its intensity enhances and its peak position keeps unchanged. These results indicate that the formation of the spin singlet dimers is accompanied with the occurrence of the local structure distortion of MoO6 octahedra, providing evidence for the strong spin-phonon coupling in the double perovskite Ba2YMoO6.

Shile Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Investigation of spin-phonon coupling in triangular-lattice antiferromagnet AgCrS2 by Infrared Transmission Spectroscopy
    Journal of Magnetism and Magnetic Materials, 2016
    Co-Authors: Wenshuai Gao, Youming Zou, Shile Zhang, Liran Shi, Zhengcai Xia, Zhongwen Ouyang, Bingjie Liu, Lei Zhang
    Abstract:

    Abstract In this work, we have investigated the spin-phonon coupling in the triangular-lattice antiferromagnet AgCrS 2 by means of Infrared Transmission Spectroscopy. At 300 K, four IR active phonon modes having the typical profile expected for an insulating material have been observed. These phonon modes are found to continuously harden upon cooling due to the slight shrinkage of the lattice. The splitting of a phonon mode and the occurrence of two new phonon modes are observed at T N , providing evidences for strong spin-phonon coupling. It is noted that phonon eigenfrequencies show significant deviations from the anharmonic contribution at temperatures much higher than T N , which is clearly determined by the strong spin fluctuations. Our results suggest that spin-phonon coupling has strong influence even in PM state in this material.

  • Spin-phonon coupling probed by Infrared Transmission Spectroscopy in the double perovskite Ba2YMoO6
    Journal of Applied Physics, 2013
    Co-Authors: Youming Zou, Shile Zhang, Lei Zhang, Langsheng Ling, Yuheng Zhang
    Abstract:

    In this work, we report a study on the Infrared Transmission Spectroscopy of the double perovskite Ba2YMoO6. At 300 K, three bands are observed at ∼255.1 cm−1, ∼343.4 cm−1, and ∼561.5 cm−1, which are related to the motion between the cation Ba2+ and the anion YMO6−2, the Y-O stretching motion, and the stretching vibration of the MoO6 octahedron, respectively. These modes continue to harden upon cooling owing to the shrink of the lattice constant. When the temperature decreases to T≤130 K around which the spin singlet dimer begins to form, an additional phonon mode appears at ∼611 cm−1, suggesting the occurrence of local distortion of MoO6 octahedra. With further decrease of the temperature, its intensity enhances and its peak position keeps unchanged. These results indicate that the formation of the spin singlet dimers is accompanied with the occurrence of the local structure distortion of MoO6 octahedra, providing evidence for the strong spin-phonon coupling in the double perovskite Ba2YMoO6.

Heribert Wiedemeier - One of the best experts on this subject based on the ideXlab platform.