Microstructure and Magnetic Properties of Sn<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript>Ni<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>O<Subscript>2</Subscript> Thin Films Prepared by Flash Evaporation Technique

An effort was made to develop semiconductor oxide-based room temperature dilute magnetic semiconductor (DMS) thin films based on wide band gap and transparent host lattice with transition metal substitution. The Sn\(_{\mathrm {1}-x}\)Ni\(_{x}\textit {O}_{\mathrm {2}}\) (\(x\,= \mathrm {0.00, 0.03, 0.05, 0.07, 0.10, and \,0.15}\)) thin film samples were prepared on glass substrates by flash evaporation technique. All the samples were shown single phase crystalline rutile structure of host SnO\(_{\mathrm {2}}\) with dominant (110) orientation. The Ni substitution promotes reduction of average crystallite size in SnO\(_{\mathrm {2}}\) as evidenced from the reduction of crystallite size from 40 (SnO\(_{\mathrm {2}}\)) to 20 nm (Sn\(_{\mathrm {0.85}}\)Ni\(_{\mathrm {0.15}}\textit {O}_{\mathrm {2}}\)). In the energy dispersive spectra as well as X-ray photoelectron spectra of all the samples show, the chemical compositions are close to stoichiometric with noticeable oxygen deficiency. The crystalline films were formed by coalescence of oval-shaped polycrystalline particles of 100 nm size as evidenced from the electron micrographs. The energy band gap of DMS films decreases from 4 (SnO\(_{\mathrm {2}}\)) to 3.8 eV (x \(=\) 0.05) with increase of Ni content. The magnetic hysteresis loops of all the samples at room temperature show soft ferromagnetic nature except for SnO\(_{\mathrm {2}}\) film. The SnO\(_{\mathrm {2}}\) films show diamagnetic nature and it converts into ferromagnetic upon substitution of 3 % Sn\(^{\mathrm {4+}}\) by Ni\(^{\mathrm {2+}}\). The robust intrinsic ferromagnetism (saturation magnetization, 21 emu/cm\(^{\mathrm {3}}\)). Further increase of Ni content weakens ferromagnetic strength due to Ni-O antiferromagnetic interactions among the nearest neighbour Ni ions via O\(^{\mathrm {2-}}\) ions. The observed magnetic properties were best described by bound magnetic polarons model.     

Comparisons of Experimental Fracture Toughness Testing Methods of Al6061–Graphite Particulate Composites

Journal of Failure Analysis and Prevention - This paper exhibits the investigative work conducted on fracture toughness of aluminum–graphite metal matrix composites. The materials chosen for...     

Effect of substrate temperature on the physical properties of In2O3:Mo films: Prepared by an activated reactive evaporation

Transparent and high conductive molybdenum doped indium oxide (IMO) thin films have been deposited on glass substrates by activated reactive evaporation. The effect of substrate temperature on the structure, surface morphology, electrical, optical and photoluminescence properties of these films were systematically examined and it was found that crystallinity and growth orientation of the films were significantly influenced by substrate temperature. In addition the films exhibited a low electrical resistivity of 5.2 × 10⁻⁴ Ω cm with an optical transmittance 90% in the visible region of the solar spectrum at a substrate temperature of 573 K. Intensive blue PL bands at 415 and 440 nm were observed in the photoluminescence spectrum at room temperature.     

Taguchi approach to influence of processing parameters onerosive wear behaviour of Al7034-T6 composites

Taguchi technique was used to predict the influence of processing parameters on the erosive wear behavior Al7034-T6 composite reinforced with SiC and Al₂O₃ particles in different mass fractions. These hybrid metal matrix composites (HMMCs) were fabricated by using a simple technique called stir casting technique. Scanning electron microscope (SEM) was used to study the surface morphology of the composite and its evolution according to processing time. The design of experiment (DOE) based on Taguchi's L₁₆ orthogonal array was used to identify various erosion trials. The most influencing parameter affecting the wear rate was identified. The results indicate that erosion wear rate of this hybrid composite is greatly influenced more by filler content and impact velocity respectively compared to other factors. This also shows the significant wear resistance with the increase in the filler contents of SiC and Al₂O₃ particles, respectively.     

Physical Properties of Sn1−x Fe x O2 Powders Using Solid State Reaction

Iron-doped SnO₂ diluted magnetic semiconducting powders (Sn_1?x Fe _x O₂, x=0.00, 0.03, 0.05, 0.07, 0.10, and 0.15) were synthesized by a simple solid state reaction followed by vacuum annealing and studied the effect of Fe dopant concentrations on structural, optical, and magnetic properties of the synthesized samples. From the X-ray diffraction, it was confirmed that the samples prepared at lower dopant concentrations were tetragonal in structure whereas the samples prepared at higher dopant concentration exhibited orthorhombic SnO and Fe₂O₃ phases along with tetragonal SnO₂ structure. FT-IR spectrum has been used to confirm the formation of Sn–O bond. The optical band gap of the Sn_1?x Fe _x O₂ powders was increased from 3.6 eV to 3.7 eV with increase of dopant concentration. Raman spectroscopy measurement revealed that the broadening of the most intense Raman peak observed at 630 cm^?1 with Fe doping, conforming that the Fe ions are substituted at the Sn sites in the SnO₂ lattice. Vibrating sample magnetometer measurements confirmed that the Sn_1?x Fe _x O₂ powders were ferromagnetic at room temperature.     

Structural and Magnetic Properties of Co diffused CdTe Nanocrystalline Thin Films Deposited by Electron Beam Evaporation

Co diffused cadmium telluride (CdTe) nanocrystalline thin films with different Co content were prepared by depositing CdTe/Co stacked layers on glass substrates at 373 K using electron beam evaporation technique. The effect of Co content on structural, morphological, chemical, Raman, and magnetic studies were carried out. X-ray diffraction (XRD) patterns confirmed that all Co diffused CdTe films are in zinc blende structure. The lattice parameter increased with increase of Co content. The high-resolution scanning electron microscopy (HRSEM) images illustrated the grain size of the films. EDAX data confirmed the presence of Co, Cd, and Te with nearly stoichiometic. Raman spectra revealed peaks corresponding to A1, TO, and LO modes of CdTe and gradual shift in peak position. The increase in intensity confirmed the incorporation of Co into CdTe host lattice. Magnetic measurements showed a clear well-defined room temperature ferromagnetic hysteresis loop.     

Structural,optical and magnetic properties of Cu doped CdSe powders prepared by solid state reaction method

Cu doped CdSe powders were synthesized by solid state reaction method and studied the effect of Cu doping concentration on structural, optical and magnetic properties of the prepared samples. From XRD study it was found that the lattice constant increased with increase of Cu doping concentration. A clear blue shift was observed in the samples from optical studies. From the magnetic measurements, it was found that the samples were room temperature ferromagnetic in nature and strength of magnetic moment increased with increase of doping concentration. These synthesized powders are dilute magnetic semiconductors and are very promising candidates for ‘Spintronic’ device applications.     

Effect of sputtering power on the physical properties of dc magnetron sputtered copper oxide thin films

Cuprous oxide films were deposited on glass substrates using dc magnetron sputtering technique by sputtering of pure copper target in a mixture of argon and oxygen atmosphere under various sputtering powers in the range 0.38–1.50 W cm⁻². The influence of sputtering power on the structural, electrical and optical properties was systematically studied. The films were polycrystalline in nature with cubic structure. The films formed at sputtering powers ≤0.76 W cm⁻² exhibited mixed phase of Cu₂O and CuO while those formed at 1.08 W cm⁻² were single phase Cu₂O. The single-phase Cu₂O films formed at a sputtering power of 1.08 W cm⁻² showed electrical resistivity of 46 Ω cm, Hall mobility of 5.7 cm² V⁻¹ s⁻¹ and optical band gap of 2.04 eV.     

Physical properties of flash evaporated In2O3 films prepared at different substrate temperatures

Indium oxide (In₂O₃) thin films were prepared by flash evaporated technique under various substrate temperatures in the range of 303-673 K and systematically studied the structural, electrical and optical properties of the deposited films. The films formed at substrate temperatures of < 373 K were amorphous while those deposited at higher substrate temperatures (≥ 373 K) were polycrystalline in nature. The optical band gap of the films decreased from 3.71 eV to 2.86 eV with the increase of substrate temperature from 303 K to 673 K. Figure of merit of the films increased from 2.8 × 10³ Ω^− 1 cm^− 1 to 4.2 × 10³ Ω^− 1 cm^− 1 with increasing substrate temperature from 303 K to 573 K, thereafter decreased to 2.2 × 10³ Ω^− 1 cm^− 1 at higher temperature of 673 K.     

Improved under damped oscillator properties of polymer blends for electronic applications

Mechanics of Time-Dependent Materials - Modified polymer blends demonstrated the desirable properties and performance suitable for various applications. In the present investigation, we prepared...