scholarly journals Fabrication and Magnetic Properties of CoNiAl Ferromagnetic Shape Memory Alloy Thin Films

2009 ◽  
Vol 635 ◽  
pp. 167-172 ◽  
Author(s):  
Rajini B. Kanth ◽  
D. Bhattacharjya ◽  
P.K. Mukhopadhyay
Keyword(s):  
Thin Films ◽  
Shape Memory ◽  
Resistivity Measurement ◽  
X Ray Diffraction ◽  
Ferromagnetic Shape Memory Alloys ◽  
Transformation Temperatures ◽  
X Ray ◽  
Fine Grained ◽  
Glass Substrates ◽  
Ferromagnetic Shape Memory

Study o Ferromagnetic shape memory alloys (FSMAs) is an interesting topic of present day research because of their large magnetic field induced shape recovery. They are important materials for the development of sensors and actuator based applications. Attempt for miniaturization of these actuators and sensors have led to the study of thin films. Bulk CoNiAl alloys are promising FSMAs because of their higher ductility and large range of control over the magnetic and structural transformation temperatures. To investigate the physical properties in thin film form we fabricated CoNiAl alloy films by D.C. sputtering method on glass substrates (kept at room temperature) under various conditions. They were annealed in vacuum at 500 0C for 1h. The samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and ellipsometry. Thickness of the films was found to be lying between 70 and 272 nm. Fine grained microstructure was found for all the deposited films. The transformation temperatures of the samples were taken from the resistivity measurement done between 80 and 350 K. Magnetization measurements were also done between 80 and 400 K by using a vibrating sample magnetometer, but the Curie temperatures of the present films were not found to be below 400 K and magnetoelastic couplings were found to be rather weak.

Structural Characterization of Co70-xNixGa30 Ferromagnetic Shape Memory Alloys

2008 ◽  
Vol 52 ◽  
pp. 103-108 ◽  
Author(s):  
Sidananda Sarma ◽  
A. Srinivasan
Keyword(s):  
Magnetic Susceptibility ◽  
Shape Memory ◽  
Room Temperature ◽  
Structural Parameters ◽  
Ac Magnetic Susceptibility ◽  
X Ray Diffraction ◽  
Ferromagnetic Shape Memory Alloys ◽  
Two Phase ◽  
X Ray ◽  
Ferromagnetic Shape Memory

Polycrystalline ingots of Co70–xNixGa30 (20 ≤ x ≤ 26) ferromagnetic shape memory alloy (FSMA) were prepared by arc melting elemental powders followed by homogenization at 1230 °C for 24 hrs and quenching in liquid nitrogen. Room temperature X-Ray diffraction (XRD) patterns of as-quenched samples exhibited single-phase tetragonal structure for alloy compositions with x = 21 to 26, and a two-phase structure (cubic A2-phase along with weak tetragonal phase) for the alloy with x = 20. Rietveld refinement was performed on the X-ray diffraction patterns to obtain the refined structural parameters. Differential Scanning Calorimeter (DSC) curves recorded from 30 °C to 250 °C revealed martensite-austenite and austenite-martensite transformations in all alloys except the alloy with composition x = 20. Low temperature ac magnetic susceptibility measurements confirmed the existence of martensitic transformations in the alloy with x = 20. The structural transformation temperatures show a linear variation with e/a ratio. All the alloys were ferromagnetic at room temperature. Curie temperature was determined using a high temperature ac magnetic susceptibility measurement set-up.

X- ray diffraction and dielectric properties of PbSe thin films

2019 ◽  
Vol 15 (34) ◽  
pp. 1-14
Author(s):  
Bushra A. Hasan
Keyword(s):  
Thin Films ◽  
Thermal Activation ◽  
Thermal Evaporation ◽  
Thermal Activation Energy ◽  
Dielectric Constants ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
Thermal Evaporation Method ◽  
X Ray ◽  
Glass Substrates

Lead selenide PbSe thin films of different thicknesses (300, 500, and 700 nm) were deposited under vacuum using thermal evaporation method on glass substrates. X-ray diffraction measurements showed that increasing of thickness lead to well crystallize the prepared samples, such that the crystallite size increases while the dislocation density decreases with thickness increasing. A.C conductivity, dielectric constants, and loss tangent are studied as function to thickness, frequency (10kHz-10MHz) and temperatures (293K-493K). The conductivity measurements confirm confirmed that hopping is the mechanism responsible for the conduction process. Increasing of thickness decreases the thermal activation energy estimated from Arhinus equation is found to decrease with thickness increasing. The increase of thickness lead to reduce the polarizability α while the increasing of temperature lead to increase α.

scholarly journals Reactive Dual Magnetron Sputtering: A Fast Method for Preparing Stoichiometric Microcrystalline ZnWO4 Thin Films

Surfaces ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 106-114
Author(s):  
Yannick Hermans ◽  
Faraz Mehmood ◽  
Kerstin Lakus-Wollny ◽  
Jan P. Hofmann ◽  
Thomas Mayer ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Photoelectron Spectroscopy ◽  
Fast Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Substrates ◽  
Post Annealing ◽  
Rf Signal ◽  
First Time

Thin films of ZnWO4, a promising photocatalytic and scintillator material, were deposited for the first time using a reactive dual magnetron sputtering procedure. A ZnO target was operated using an RF signal, and a W target was operated using a DC signal. The power on the ZnO target was changed so that it would match the sputtering rate of the W target operated at 25 W. The effects of the process parameters were characterized using optical spectroscopy, X-ray diffraction, and scanning electron microscopy, including energy dispersive X-ray spectroscopy as well as X-ray photoelectron spectroscopy. It was found that stoichiometric microcrystalline ZnWO4 thin films could be obtained, by operating the ZnO target during the sputtering procedure at a power of 55 W and by post-annealing the resulting thin films for at least 10 h at 600 °C. As FTO coated glass substrates were used, annealing led as well to the incorporation of Na, resulting in n+ doped ZnWO4 thin films.

Effects of Annealing on Microstructure and Martensitic Transition of Ni-Mn-Co-In Ferromagnetic Shape Memory Alloys

2011 ◽  
Vol 674 ◽  
pp. 171-175
Author(s):  
Katarzyna Bałdys ◽  
Grzegorz Dercz ◽  
Łukasz Madej
Keyword(s):  
Electron Microscopy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Smart Materials ◽  
Martensitic Transition ◽  
Magnetic Shape Memory ◽  
Ferromagnetic Shape Memory Alloys ◽  
Initial State ◽  
X Ray ◽  
Ferromagnetic Shape Memory

The ferromagnetic shape memory alloys (FSMA) are relatively the brand new smart materials group. The most interesting issue connected with FSMA is magnetic shape memory, which gives a possibility to achieve relatively high strain (over 8%) caused by magnetic field. In this paper the effect of annealing on the microstructure and martensitic transition on Ni-Mn-Co-In ferromagnetic shape memory alloy has been studied. The alloy was prepared by melting of 99,98% pure Ni, 99,98% pure Mn, 99,98% pure Co, 99,99% pure In. The chemical composition, its homogeneity and the alloy microstructure were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The phase composition was also studied by X-ray analysis. The transformation course and characteristic temperatures were determined by the use of differential scanning calorimetry (DSC) and magnetic balance techniques. The results show that Tc of the annealed sample was found to decrease with increasing the annealing temperature. The Ms and Af increases with increasing annealing temperatures and showed best results in 1173K. The studied alloy exhibits a martensitic transformation from a L21 austenite to a martensite phase with a 7-layer (14M) and 5-layer (10M) modulated structure. The lattice constants of the L21 (a0) structure determined by TEM and X-ray analysis in this alloy were a0=0,4866. The TEM observation exhibit that the studied alloy in initial state has bigger accumulations of 10M and 14M structures as opposed from the annealed state.

Effect of Substrate Temperature on the Electrochromic Properties of Cobalt Hydroxide Thin Films Prepared by Reactive Sputtering

2011 ◽  
Vol 1328 ◽  
Author(s):  
KyoungMoo Lee ◽  
Yoshio Abe ◽  
Midori Kawamura ◽  
Hidenobu Itoh
Keyword(s):  
Thin Films ◽  
Substrate Temperature ◽  
Indium Tin Oxide ◽  
Large Change ◽  
Amorphous Structure ◽  
Cobalt Hydroxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Substrates ◽  
Substrate Temperatures

ABSTRACTCobalt hydroxide thin films with a thickness of 100 nm were deposited onto glass, Si and indium tin oxide (ITO)-coated glass substrates by reactively sputtering a Co target in H2O gas. The substrate temperature was varied from -20 to +200°C. The EC performance of the films was investigated in 0.1 M KOH aqueous solution. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy of the samples indicated that Co3O4 films were formed at substrate temperatures above 100°C, and amorphous CoOOH films were deposited in the range from 10 to -20°C. A large change in transmittance of approximately 26% and high EC coloration efficiency of 47 cm2/C were obtained at a wavelength of 600 nm for the CoOOH thin film deposited at -20°C. The good EC performance of the CoOOH films is attributed to the low film density and amorphous structure.

Electrochemical Deposition and Characterization of Cd-Fe-Se Thin Films

2009 ◽  
Vol 68 ◽  
pp. 69-76 ◽  
Author(s):  
S. Thanikaikarasan ◽  
T. Mahalingam ◽  
K. Sundaram ◽  
Tae Kyu Kim ◽  
Yong Deak Kim ◽  
...  
Keyword(s):  
Thin Films ◽  
Hexagonal Structure ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Iron Selenide ◽  
Glass Substrates ◽  
Diffraction Patterns ◽  
Cadmium Iron Selenide ◽  
Deposited Films

Cadmium iron selenide (Cd-Fe-Se) thin films were deposited onto tin oxide (SnO2) coated conducting glass substrates from an aqueous electrolytic bath containing CdSO4, FeSO4 and SeO2 by potentiostatic electrodeposition. The deposition potentials of Cadmium (Cd), Iron (Fe), Selenium (Se) and Cadmium-Iron-Selenide (Cd-Fe-Se) were determined from linear cathodic polarization curves. The deposited films were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive analysis by x-rays (EDX) and optical absorption techniques, respectively. X-ray diffraction patterns shows that the deposited films are found to be hexagonal structure with preferential orientation along (100) plane. The effect of FeSO4 concentration on structural, morphological, compositional and optical properties of the films are studied and discussed in detail.

Influence of Copper Concentration on the Structural and Optical Properties of Chemically Deposited CuSbS2 Thin Films

2016 ◽  
Vol 19 (1) ◽  
pp. 015-019 ◽  
Author(s):  
Jebadurai Joy Jeba Vijila ◽  
Kannusamy Mohanraj ◽  
Sethuramachandran Thanikaikarasan ◽  
Ganesan Sivakumar ◽  
Thaiyan Mahalingam ◽  
...  
Keyword(s):  
Thin Films ◽  
Field Emission ◽  
Secondary Phase ◽  
Diffraction Field ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Substrates ◽  
Simple Chemical ◽  
Scanning Electron

Thin films of CuSbS2 have been deposited on ultrasonically cleaned glass substrates using a simple chemical bath deposition technique. Prepared films have been characterized using X-ray diffraction, Field Emission Scanning Electron Microscopy and UV-Vis-NIR spectroscopic techniques, respectively. X-ray diffraction analysis revealed that the prepared films possess polycrystalline in nature with orthorhombic CuSbS2 in addition to secondary phase of monoclinic Cu3SbS3 and cubic Cu12Sb4S13 for different copper concentrations. Field Emission Scanning Electron Spectroscopic analysis showed that the prepared films possess spherical shaped grains with irregular shaped clusters. Optical absorption analysis showed that the prepared films possess band gap value in the range between 1.7 and 2.4 eV.

Growth of Copper Telluride Thin Films using Electrodeposition

2018 ◽  
Vol 21 (1) ◽  
pp. 015-019
Author(s):  
P. Jeyakumar ◽  
S. Thanikaikarasan ◽  
B. Natarajan ◽  
T. Mahalingam ◽  
Luis Ixtlilco
Keyword(s):  
Thin Films ◽  
X Ray Diffraction ◽  
Electrodeposition Technique ◽  
Cyclic Voltammetric ◽  
Voltammetric Analysis ◽  
Copper Telluride ◽  
X Ray ◽  
Microstructural Parameters ◽  
Glass Substrates ◽  
Deposited Films

Copper Telluride thin films have been prepared on Fluorine doped Tin Oxide coated conducting glass substrates using electrodeposition technique. Cyclic voltammetric analysis has been carried out to analyze the growth mechanism of the deposited films. Thickness value of the deposited films has been estimated using Stylus profilometry. X-ray diffraction pattern revealed that the prepared films possess polycrystalline in nature. Microstructural parameters such as crystallite size, strain and dislocation density are evaluated using observed X-ray diffraction data. Optical absorption analysis showed that the prepared films are found to exhibit band gap value around 2.03 eV.

Effects on Structural, Electronic Transport & Optical Properties of Doped & Undoped ZnTe Thin Films for CdTe/CdS Solar Cells

2012 ◽  
Vol 510-511 ◽  
pp. 89-97
Author(s):  
G.H. Tariq ◽  
M. Anis-ur-Rehman
Keyword(s):  
Thin Films ◽  
Buffer Layer ◽  
Growth Parameters ◽  
Optical Measurements ◽  
X Ray Diffraction ◽  
Contact Materials ◽  
X Ray ◽  
Glass Substrates ◽  
Evaporation Technique ◽  
Znte Thin Films

To overcome the naturally existing Schottky barrier problem between p-CdTe and any metal, an intermediate semiconductor thin buffer layer is a better choice prior to the final metallization for contact. Among many investigated back contact materials the ZnTe is suitable as a buffer layer. ZnTe thin films were deposited onto glass substrates by the thermal evaporation technique under vacuum ~2×10-5mbar. Undoped ZnTe thin films are highly resistive, extrinsic doping of Cu was made to improve the electrical conductivity. Films were doped by immersing in Cu NO32.5H2O solutions for Cu doping. To optimize the growth parameters the prepared films were characterized using various techniques. The structural analysis of these films was performed by X-ray diffraction (XRD) technique and optical transmission. X-ray diffraction identified the phases present in these films and also observed that the prepared films were polycrystalline. Also the spectral dependence of absorption coefficient was determined from spectrophotometer. Energy band gap index were calculated from obtained optical measurements data.

Effect of Second Complexing Agent of N2H4 on the Optical and Structural Properties of ZnS Thin Films

2013 ◽  
Vol 591 ◽  
pp. 297-300
Author(s):  
Huan Ke ◽  
Shu Wang Duo ◽  
Ting Zhi Liu ◽  
Hao Zhang ◽  
Xiao Yan Fei
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Structural Properties ◽  
Band Gaps ◽  
Complexing Agent ◽  
X Ray Diffraction ◽  
Sphalerite Structure ◽  
X Ray ◽  
Glass Substrates ◽  
Zns Films

ZnS films have been deposited on glass substrates by chemical bath deposition (CBD). The optical and structural properties were analyzed by UV-VIS spectrophotometer and X-ray diffraction (XRD). The results showed that the prepared thin films from the solution using N2H4 as second complexing agent were thicker than those from the solution without adding N2H4 in; this is due to using second complexing agent of N2H4, the deposition mechanisms change which is conductive to heterogeneous deposition. When using N2H4 as second complexing agent, the crystallinity of ZnS thin films improved with a significant peak at 2θ=28.96°which can be assigned to the (111) reflection of the sphalerite structure. The transmittances of the prepared films from the solution adding N2H4 in as second complexing agent were over 85%, compared to those from the solution without N2H4 (over 95%). The band gaps of the ZnS films from the solution using N2H4 as second complexing agent were larger (about 4.0eV) than that from those from the solution without N2H4 (about 3.98eV), which indicated that the prepared ZnS films from the solution adding N2H4 in as second complexing agent were better used as buffer layer of solar cells with adequate optical properties. In short, using N2H4 as second complexing agent, can greatly improve the optical and structural properties of the ZnS thin films.

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