scholarly journals Asymmetric polarization and hysteresis behaviour in ferroelectric P(VDF–TrFE) (76 : 24) copolymer thin films spatially resolved via LIMM

2015 ◽  
Vol 17 (12) ◽  
pp. 7767-7774 ◽  
Author(s):  
T. Putzeys ◽  
M. Wübbenhorst

The role of charges for achieving and stabilizing the ferroelectric polarization in PVDF–TrFE (76 : 24) is revisited using advanced photothermal methods.

2007 ◽  
Vol 21 (18n19) ◽  
pp. 3310-3313
Author(s):  
EUN-MI CHOI ◽  
HYUN-SOOK LEE ◽  
JAE YEAP LEE ◽  
SUNG-IK LEE ◽  
Å. A. F. OLSEN ◽  
...  

We measured the magneto-optical images (MOIs) and the magnetic hysteresis (M – H) curves of c-axis-oriented MgB 2 thin films to investigate the flux penetration in the form of dendritic avalanches. In order to understand the role of the thermal effects, we prepared Au -coated MgB 2 thin films with different thicknesses of gold. While the MOI provides a spatially resolved flux pattern, the M – H curve presents global and average information about the flux noise associated with avalanches. These two types of measurements complement each other. The upper threshold field, above which the flux noise disappears, was determined from the M-H curves while the lower threshold field was determined from both the M – H curves and the MO images. The field range where the flux penetrates via avalanches is found to be smaller for thicker gold layers. These results are important for many superconducting applications.


Author(s):  
L.J. Chen ◽  
Y.F. Hsieh

One measure of the maturity of a device technology is the ease and reliability of applying contact metallurgy. Compared to metal contact of silicon, the status of GaAs metallization is still at its primitive stage. With the advent of GaAs MESFET and integrated circuits, very stringent requirements were placed on their metal contacts. During the past few years, extensive researches have been conducted in the area of Au-Ge-Ni in order to lower contact resistances and improve uniformity. In this paper, we report the results of TEM study of interfacial reactions between Ni and GaAs as part of the attempt to understand the role of nickel in Au-Ge-Ni contact of GaAs.N-type, Si-doped, (001) oriented GaAs wafers, 15 mil in thickness, were grown by gradient-freeze method. Nickel thin films, 300Å in thickness, were e-gun deposited on GaAs wafers. The samples were then annealed in dry N2 in a 3-zone diffusion furnace at temperatures 200°C - 600°C for 5-180 minutes. Thin foils for TEM examinations were prepared by chemical polishing from the GaA.s side. TEM investigations were performed with JE0L- 100B and JE0L-200CX electron microscopes.


Author(s):  
L. Tang ◽  
G. Thomas ◽  
M. R. Khan ◽  
S. L. Duan

Cr thin films are often used as underlayers for Co alloy magnetic thin films, such as Co1, CoNi2, and CoNiCr3, for high density longitudinal magnetic recording. It is belived that the role of the Cr underlayer is to control the growth and texture of the Co alloy magnetic thin films, and, then, to increase the in plane coercivity of the films. Although many epitaxial relationship between the Cr underlayer and the magnetic films, such as ﹛1010﹜Co/ {110﹜Cr4, ﹛2110﹜Co/ ﹛001﹜Cr5, ﹛0002﹜Co/﹛110﹜Cr6, have been suggested and appear to be related to the Cr thickness, the texture of the Cr underlayer itself is still not understood very well. In this study, the texture of a 2000 Å thick Cr underlayer on Nip/Al substrate for thin films of (Co75Ni25)1-xTix dc-sputtered with - 200 V substrate bias is investigated by electron microscopy.


Author(s):  
C. Ewins ◽  
J.R. Fryer

The preparation of thin films of organic molecules is currently receiving much attention because of the need to produce good quality thin films for molecular electronics. We have produced thin films of the polycyclic aromatic, perylene C10H12 by evaporation under high vacuum onto a potassium chloride (KCl) substrate. The role of substrate temperature in determining the morphology and crystallography of the films was then investigated by transmission electron microscopy (TEM).The substrate studied was the (001) face of a freshly cleaved crystal of KCl. The temperature of the KCl was controlled by an electric heater or a cold finger. The KCl was heated to 200°C under a vacuum of 10-6 torr and allowed to cool to the desired temperature. The perylene was then evaporated over a period of one minute from a molybdenum boat at a distance of 10cm from the KCl. The perylene thin film was then backed with an amorphous layer of carbon and floated onto copper microscope grids.


2021 ◽  
Vol 46 (5) ◽  
pp. 4137-4153
Author(s):  
Neha Verma ◽  
Rob Delhez ◽  
Niek M. van der Pers ◽  
Frans D. Tichelaar ◽  
Amarante J. Böttger

Author(s):  
Hendrik Linz ◽  
Henrik Beuther ◽  
Maryvonne Gerin ◽  
Javier R. Goicoechea ◽  
Frank Helmich ◽  
...  

AbstractThe far-infrared (FIR) regime is one of the wavelength ranges where no astronomical data with sub-arcsecond spatial resolution exist. None of the medium-term satellite projects like SPICA, Millimetron, or the Origins Space Telescope will resolve this malady. For many research areas, however, information at high spatial and spectral resolution in the FIR, taken from atomic fine-structure lines, from highly excited carbon monoxide (CO), light hydrides, and especially from water lines would open the door for transformative science. A main theme will be to trace the role of water in proto-planetary discs, to observationally advance our understanding of the planet formation process and, intimately related to that, the pathways to habitable planets and the emergence of life. Furthermore, key observations will zoom into the physics and chemistry of the star-formation process in our own Galaxy, as well as in external galaxies. The FIR provides unique tools to investigate in particular the energetics of heating, cooling, and shocks. The velocity-resolved data in these tracers will reveal the detailed dynamics engrained in these processes in a spatially resolved fashion, and will deliver the perfect synergy with ground-based molecular line data for the colder dense gas.


2021 ◽  
Vol 207 ◽  
pp. 116683
Author(s):  
Jun Young Lee ◽  
Gopinathan Anoop ◽  
Sanjith Unithrattil ◽  
WooJun Seol ◽  
Youngki Yeo ◽  
...  

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