scholarly journals Correlation analysis of vibration modes in physical vapour deposited Bi2Se3 thin films probed by the Raman mapping technique

2021 ◽  
Author(s):  
K. A. Niherysh ◽  
J. Andzane ◽  
M. M. Mikhalik ◽  
S. M. Zavadsky ◽  
P. L. Dobrokhotov ◽  
...  

We propose the evaluation of strain in Bi2Se3 films based on the correlation analysis of in-plane (E2g) and out-of-plane (A21g) Raman mode positions as well as the algorithm of phonon deformation potential calculation for biaxial in-plane strain.

Microscopy ◽  
2015 ◽  
Vol 64 (suppl 1) ◽  
pp. i53.1-i53
Author(s):  
Si-Young Choi ◽  
Sung-Dae Kim ◽  
Jungho Ryu

2001 ◽  
Vol 688 ◽  
Author(s):  
N.J. Donnelly ◽  
G. Catalan ◽  
C. Morros ◽  
R.M. Bowman ◽  
J.M. Gregg

AbstractThin film capacitor structures of Au / (1−x)Pb(Mg1/3Nb2/3)O3 - xPbTiO3 /(La1/2Sr1/2)CoO3 were fabricated by pulsed laser deposition on single crystal {001} MgO substrates. Films were found to be perovskite dominated and highly {001} oriented. Dielectrically, films displayed relaxorlike features, though maximum permittivity was low compared to single crystal or bulk ceramic (∼1400 at peak @1kHz, for x=0.07, 0.1 & 0.2). A field induced piezoelectric coefficient d33 was measured by piezoresponse atomic force microscopy for specific compositions x =0, × =0.07, and x =0.1 and found to be disappointingly low - indicating poor electric field induced strain. Despite this macroscopic electrostrictive coefficients Q33 were found to be (3.6 ± 0.6) ×10−2C−2m4, (2.6 ± 0.2) ×10−2C−2m4, and (0.9 ± 0.3) ×10−2C−2m4 respectively. Crystallographic electrostrictive coefficients were determined by in-situ x-ray diffraction and found to be (4.9 ± 0.2) ×10−2C−2m4 for PMN-(0.07)PT and (1.9 ± 0.1) ×10−2C−2m4 for PMN-(0.1)PT. Considering that all these Q33 values are of the same order of magnitude as found in single crystal experiments (2.5 – 3.8 ×10−2C−2m4), it is suggested that low out-of-plane strain is entirely a result of reduced polarisability rather than reduced electrostrictive coefficients in thin films relative to bulk ceramic or single crystal. An estimate was also made of the Q13 electrostrictive coefficient for PMN and PMN-(0.07)PT by measuring permittivity as a function of applied in-plane strain. The values obtained were -1.31 ×10−2C−2m4 and -0.46 ×10−2C−2m4 respectively.


Author(s):  
Alexander Konetschny ◽  
Marcel Weinhold ◽  
Christian Heiliger ◽  
Matthias Thomas Elm ◽  
Peter J. Klar

Square-shaped Ce0.8Gd0.2O2 (GDC) membranes are prepared by microstructuring techniques from (111)-oriented, polycrystalline GDC thin films. The strain state of the membranes is investigated by micro-Raman mapping using polarized excitation light....


MRS Advances ◽  
2016 ◽  
Vol 1 (37) ◽  
pp. 2635-2640 ◽  
Author(s):  
Adele Moatti ◽  
Reza Bayati ◽  
Srinivasa Rao Singamaneni ◽  
Jagdish Narayan

ABSTRACTBi-epitaxial VO2 thin films with [011] out-of-plane orientation were integrated with Si(100) substrates through TiO2/TiN buffer layers. At the first step, TiN is grown epitaxially on Si(100), where a cube-on-cube epitaxy is achieved. Then, TiN was oxidized in-situ ending up having epitaxial r-TiO2. Finally, VO2 was deposited on top of TiO2. The alignment across the interfaces was stablished as VO2(011)║TiO2(110)║TiN(100)║Si(100) and VO2(110) /VO2(010)║TiO2(011)║TiN(112)║Si(112). The inter-planar spacing of VO2(010) and TiO2(011) equal to 2.26 and 2.50 Å, respectively. This results in a 9.78% tensile misfit strain in VO2(010) lattice which relaxes through 9/10 alteration domains with a frequency factor of 0.5, according to the domain matching epitaxy paradigm. Also, the inter-planar spacing of VO2(011) and TiO2(011) equals to 3.19 and 2.50 Å, respectively. This results in a 27.6% compressive misfit strain in VO2(011) lattice which relaxes through 3/4 alteration domains with a frequency factor of 0.57. We studied semiconductor to metal transition characteristics of VO2/TiO2/TiN/Si heterostructures and established a correlation between intrinsic defects and magnetic properties.


1999 ◽  
Vol 14 (7) ◽  
pp. 2905-2911 ◽  
Author(s):  
Sangsub Kim ◽  
Tae Soo Kang ◽  
Jung Ho Je

Epitaxial (Ba0.5Sr0.5) TiO3 thin films of two different thickness (∼25 and ∼134 nm) on MgO(001) prepared by a pulsed laser deposition method were studied by synchrotron x-ray scattering measurements. The film grew initially with a cube-on-cube relationship, maintaining it during further growth. As the film grew, the surface of the film became significantly rougher, but the interface between the film and the substrate did not. In the early stage of growth, the film was highly strained in a tetragonal structure (c/a = 1.04) with the longer axis parallel to the surface normal direction. As the growth proceeded further, it relaxed to a cubic structure with the lattice parameter near the bulk value, and the mosaic distribution improved significantly in both in- and out-of-plane directions. The thinner film (∼25 nm) showed only one domain limited mainly by the film thickness, but the thicker film (∼134 nm) exhibited three domains along the surface normal direction.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniel Lordan ◽  
Guannan Wei ◽  
Paul McCloskey ◽  
Cian O’Mathuna ◽  
Ansar Masood

AbstractThe emergence of perpendicular magnetic anisotropy (PMA) in amorphous thin films, which eventually transforms the magnetic spins form an in-plane to the out-of-plane configuration, also known as a spin-reorientation transition (SRT), is a fundamental roadblock to attain the high flux concentration advantage of these functional materials for broadband applications. The present work is focused on unfolding the origin of PMA in amorphous thin films deposited by magnetron sputtering. The amorphous films were deposited under a broad range of sputtering pressure (1.6–6.2 mTorr), and its effect on the thin film growth mechanisms was correlated to the static global magnetic behaviours, magnetic domain structure, and dynamic magnetic performance. The films deposited under low-pressure revealed a dominant in-plane uniaxial anisotropy along with an emerging, however feeble, perpendicular component, which eventually evolved as a dominant PMA when deposited under high-pressure sputtering. This change in the nature of anisotropy redefined the orientation of spins from in-plane to out-of-plane. The SRT in amorphous films was attributed to the dramatic change in the growth mechanism of disorder atomic structure from a homogeneously dispersed to a porous columnar microstructure. We suggest the origin of PMA is associated with the columnar growth of the amorphous films, which can be eluded by a careful selection of a deposition pressure regime to avoid its detrimental effect on the soft magnetic performance. To the author’s best knowledge, no such report links the sputtering pressure as a governing mechanism of perpendicular magnetisation in technologically important amorphous thin films.


Author(s):  
Mohamed T. Ghoneim ◽  
Nasir Alfaraj ◽  
Galo A. Torres Sevilla ◽  
Hossain M. Fahad ◽  
Muhammad M. Hussain

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1376
Author(s):  
Mircea Nasui ◽  
Ramona Bianca Sonher ◽  
Ecaterina Ware ◽  
Andrada Daniel ◽  
Traian Petrisor ◽  
...  

We report the preparation and characterization of epitaxial LaNiO3 (LNO) thin films by chemical solution deposition method using lanthanum and nickel acetylacetonates as starting reagents dissolved in propionic acid. In order to obtain further information regarding the decomposition behavior of the film, the precursor solution was dried to obtain the precursor powder, which was investigated by thermal analyses and X-ray diffraction measurements (XRD). The LNO perovskite thin films were deposited by spin coating on SrTiO3(100) single crystal substrates. A detailed study with different crystallization temperatures (600–900 °C) at two different heating ramps (5 and 10 °C/min) was performed. Oriented LaNiO3 thin films with good out-of-plane textures were obtained with optimal surface morphologies.


Author(s):  
Kevin I. Tzou ◽  
Jonathan A. Wickert ◽  
Adnan Akay

Abstract The three-dimensional vibration of an arbitrarily thick annular disk is investigated for two classes of boundary conditions: all surfaces traction-free, and all free except for the clamped inner radius. These two models represent limiting cases of such common engineering components as automotive and aircraft disk brakes, for which existing models focus on out-of-plane bending vibration. For a disk of significant thickness, vibration modes in which motion occurs within the disk’s equilibrium plane can play a substantial role in setting its dynamic response. Laboratory experiments demonstrate that in-plane modes exist at frequencies comparable to those of out-of-plane bending even for thickness-to-diameter ratios as small as 10−1. The equations for three-dimensional motion are discretized through the Ritz technique, yielding natural frequencies and mode shapes for coupled axial, radial, and circumferential deformations. This treatment is applicable to “disks” of arbitrary dimension, and encompasses classical models for plates, bars, cylinders, rings, and shells. The solutions so obtained converge in the limiting cases to the values expected from the classical theories, and to ones that account for shear deformation and rotary inertia. The three-dimensional model demonstrates that for geometries within the technologically-important range, the natural frequencies of certain in- and out-of-plane modes can be close to one another, or even identically repeated.


Author(s):  
W. Steinchen ◽  
M. Schuth ◽  
L. X. Yang ◽  
G. Kupfer
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