Wet-Etching Induced Abnormal Phase Transition in Highly Strained VO2 /TiO2 (001) Epitaxial Film

2017 ◽  
Vol 12 (1) ◽  
pp. 1700320 ◽  
Author(s):  
Hui Ren ◽  
Shi Chen ◽  
Yuliang Chen ◽  
Zhenlin Luo ◽  
Jingtian Zhou ◽  
...  
Keyword(s):  
Phase Transition ◽  
Epitaxial Film ◽  
Wet Etching ◽  
Highly Strained

Effect of Strain on Barium Titanate Epitaxial Films

2013 ◽  
Vol 547 ◽  
pp. 139-144
Author(s):  
Lye Hock Ong ◽  
A.M. Alrub ◽  
Khian Hooi Chew
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Free Energy ◽  
Epitaxial Films ◽  
Ferroelectric Films ◽  
Eighth Order ◽  
First Order ◽  
First Order Phase Transition ◽  
Highly Strained ◽  
First Order Phase

Landau-Ginzburg free energy expression with the normalized coefficients is used to elucidate the phase transition properties of strained ferroelectric films. In particular, we investigate the need to include higher order free energy terms for epitaxial strained BaTiO3 thin films. Our study reveals that the inclusion of eighth-order expression into the free energy is crucial in determining the phase transition of highly-strained BaTiO3 epitaxial films normally grown on thick cubic substrates. The phase transition is found to be second order but the unstrained film undergoes the first order phase transition. On the order hand, the calculation based on the usual sixth-order Landau-Ginzburg expression show that the films have no phase transition, which is contrary to the experimental observations.

Dynamic study of phase transition in Bi2O3 epitaxial film induced by electrolyte gating

2019 ◽  
Vol 115 (26) ◽  
pp. 261601
Author(s):  
Lele Fan ◽  
Yiyu Zhu ◽  
Zhiqiang Wang ◽  
Sihan Zhao ◽  
Zhonghu Liu ◽  
...  
Keyword(s):  
Phase Transition ◽  
Epitaxial Film ◽  
Dynamic Study ◽  
Electrolyte Gating

Growth and phase transition characteristics of pure M-phase VO2 epitaxial film prepared by oxide molecular beam epitaxy

2013 ◽  
Vol 103 (13) ◽  
pp. 131914 ◽  
Author(s):  
L. L. Fan ◽  
S. Chen ◽  
Y. F. Wu ◽  
F. H. Chen ◽  
W. S. Chu ◽  
...  
Keyword(s):  
Phase Transition ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Epitaxial Film ◽  
M Phase

scholarly journals N+ Irradiation and Substrate-Induced Variability in the Metamagnetic Phase Transition of FeRh Films

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 661
Author(s):  
Steven P. Bennett ◽  
Samuel W. LaGasse ◽  
Marc Currie ◽  
Olaf Van’t Erve ◽  
Joseph C. Prestigiacomo ◽  
...  
Keyword(s):  
Phase Transition ◽  
Surface Morphology ◽  
Epitaxial Film ◽  
Lattice Mismatch ◽  
Ion Irradiation ◽  
Growth Conditions ◽  
Large Lattice ◽  
Magnetron Sputter Deposition ◽  
Weber Type ◽  
Large Lattice Mismatch

Metamagnetic FeRh has been the focus of numerous studies for its highly unique antiferromagnetic (AF) to ferromagnetic (FM) metamagnetic transition. While this phase transition usually occurs above room temperature (often Tc > 400 K), both ion irradiation and strained epitaxial growth have been used to bring it to applicable temperatures. Nevertheless, cross sample variability is pervasive in these studies. Here we explore the optical and magnetic properties of 35 nm thick FeRh grown by magnetron sputter deposition simultaneously on two different single crystal substrates: epitaxially on MgO (001) and highly strained with large lattice mismatch on Al2O3 (1000). We then irradiate the epitaxial film with 5 keV N+ ions to introduce disorder (and to a lesser extent, modify chemical composition) without effecting the surface morphology. We find that the phase-transitional properties of both films are strikingly different due to the large lattice mismatch, despite being grown in tandem with nominally identical growth conditions including Fe/Rh stoichiometry, pressure, and temperature. We observe that N+ implantation lowers Tc by ~60 K, yielding a sample with nominally the same transition temperature as the non-epitaxial film on sapphire, yet with a significantly increased magnetic moment, a larger magnetization change and a more abrupt transition profile. We attribute these differences to the Volmer-Weber type growth mode induced by the sapphire substrate and the resulting rougher surface morphology.

scholarly journals Origin of thickness dependence of structural phase transition temperatures in highly strained BiFeO3 thin films

APL Materials ◽  
2016 ◽  
Vol 4 (3) ◽  
pp. 036106 ◽  
Author(s):  
Yongsoo Yang ◽  
Christianne Beekman ◽  
Wolter Siemons ◽  
Christian M. Schlepütz ◽  
Nancy Senabulya ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Thickness Dependence ◽  
Transition Temperatures ◽  
Bifeo3 Thin Films ◽  
Phase Transition Temperatures ◽  
Highly Strained

Atomic Visualization of the Phase Transition in Highly Strained BiFeO3 Thin Films with Excellent Pyroelectric Response

Nano Energy ◽  
2015 ◽  
Vol 17 ◽  
pp. 72-81 ◽  
Author(s):  
Chung-Hua Chiu ◽  
Wen-I Liang ◽  
Chun-Wei Huang ◽  
Jui-Yuan Chen ◽  
Yun-Ya Liu ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Bifeo3 Thin Films ◽  
Highly Strained ◽  
Pyroelectric Response

Microstructure of laser-irradiated, conducting Kapton polyimide

1995 ◽  
Vol 53 ◽  
pp. 502-503
Author(s):  
D. L. Callahan ◽  
Z. Ball ◽  
H. M. Phillips ◽  
R. Sauerbrey
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Film Surface ◽  
Cross Sectional ◽  
General Utility ◽  
Transmission Electron ◽  
Considerable Debate ◽  
Potential Applications

Ultraviolet laser-irradiation can be used to induce an insulator-to-conductor phase transition on the surface of Kapton polyimide. Such structures have potential applications as resistors or conductors for VLSI applications as well as general utility electrodes. Although the percolative nature of the phase transformation has been well-established, there has been little definitive work on the mechanism or extent of transformation. In particular, there has been considerable debate about whether or not the transition is primarily photothermal in nature, as we propose, or photochemical. In this study, cross-sectional optical microscopy and transmission electron microscopy are utilized to characterize the nature of microstructural changes associated with the laser-induced pyrolysis of polyimide.Laser-modified polyimide samples initially 12 μm thick were prepared in cross-section by standard ultramicrotomy. Resulting contraction in parallel to the film surface has led to distortions in apparent magnification. The scale bars shown are calibrated for the direction normal to the film surface only.

The structure of membranes and membrane proteins embedded in amorphous ice

1992 ◽  
Vol 50 (1) ◽  
pp. 432-433
Author(s):  
Uwe Lücken ◽  
Joachim Jäger
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Membrane Proteins ◽  
Phase Transition Temperature ◽  
Lipid Vesicles ◽  
Freezing Stress ◽  
Amorphous Ice ◽  
Different Temperatures ◽  
Band Pass ◽  
Lipid Polymorphism

TEM imaging of frozen-hydrated lipid vesicles has been done by several groups Thermotrophic and lyotrophic polymorphism has been reported. By using image processing, computer simulation and tilt experiments, we tried to learn about the influence of freezing-stress and defocus artifacts on the lipid polymorphism and fine structure of the bilayer profile. We show integrated membrane proteins do modulate the bilayer structure and the morphology of the vesicles.Phase transitions of DMPC vesicles were visualized after freezing under equilibrium conditions at different temperatures in a controlled-environment vitrification system. Below the main phase transition temperature of 24°C (Fig. 1), vesicles show a facetted appearance due to the quasicrystalline areas. A gradual increase in temperature leads to melting processes with different morphology in the bilayer profile. Far above the phase transition temperature the bilayer profile is still present. In the band-pass-filtered images (Fig. 2) no significant change in the width of the bilayer profile is visible.

Electron Microscope study of commensurate-incommensurate phase transition in BaZnGeO4

1990 ◽  
Vol 48 (4) ◽  
pp. 172-173
Author(s):  
Naoki Yamamoto ◽  
Makoto Kikuchi ◽  
Tooru Atake ◽  
Akihiro Hamano ◽  
Yasutoshi Saito
Keyword(s):  
Phase Transition ◽  
Electron Microscope Study ◽  
Room Temperature ◽  
Hexagonal Lattice ◽  
Ferroelectric Materials ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Periodic Arrays ◽  
Modulation Wave Vector

BaZnGeO4 undergoes many phase transitions from I to V phase. The highest temperature phase I has a BaAl2O4 type structure with a hexagonal lattice. Recent X-ray diffraction study showed that the incommensurate (IC) lattice modulation appears along the c axis in the III and IV phases with a period of about 4c, and a commensurate (C) phase with a modulated period of 4c exists between the III and IV phases in the narrow temperature region (—58°C to —47°C on cooling), called the III' phase. The modulations in the IC phases are considered displacive type, but the detailed structures have not been studied. It is also not clear whether the modulation changes into periodic arrays of discommensurations (DC’s) near the III-III' and IV-V phase transition temperature as found in the ferroelectric materials such as Rb2ZnCl4.At room temperature (III phase) satellite reflections were seen around the fundamental reflections in a diffraction pattern (Fig.1) and they aligned along a certain direction deviated from the c* direction, which indicates that the modulation wave vector q tilts from the c* axis. The tilt angle is about 2 degree at room temperature and depends on temperature.

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