Materials Literature
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The authors report the effects of Cs doping on the field emission properties of a five-shell single carbon nanotube. The chiral indices of each shell of this carbon nanotube have been determined using nanobeam electron diffraction, which has four semiconducting shells and one metallic shell in the middle. From the Fow…
A study of crack patterns in laponite films of different thickness is presented. Two cracking regimes are observed. The earlier, with a higher rate of desiccation and shrinking, has predominantly 4-fold vertices in the crack network, while the later regime has less volume shrinking and forms mainly 3-fold vertices. Th…
Zn 1 − x Mg x O films were grown by radio-frequency reactive magnetron sputtering using mixture of nitrogen and argon as sputtering gases. It was found that Mg concentration, structures, electrical properties, and band gaps of the films can be tuned by changing nitrogen partial pressure ratio of the sputtering gases.…
The elastic deformation of nanometer-sized metal crystals is achieved by encapsulating them in carbon nanotubes or carbon onions. Electron irradiation of these core-shell particles leads to high pressure in their center due to a shrinkage of the graphitic shells. Pressures in the range of 10–30GPa are found by measuri…
X-ray diffraction studies of nanomolybdenum and nanonickel were conducted using a synchrotron source under nonhydrostatic compression up to pressures of 37 and 56GPa, respectively. No phase transitions were found up to the maximum pressure studied. Bulk modulus and its pressure derivative were calculated from the pres…
The effect of an externally applied electric field in single-walled carbon nanotubes was studied using a thin-film transistor configuration. Under the electric field, the optical spectra displayed redshifts and broadening. These phenomena present evidence of the Stark effect in single-walled carbon nanotubes. The find…
The field-dependent complex impedance (CI) spectroscopy is employed to clarify the origins of ac magnetoimpedance (MI) effects at room temperature near the conduction threshold of [La0.67Sr0.33MnO3(113)]1−x∕[La1.67Sr1.33Mn2O7(327)]x composites. The field-dependent CI spectra in 113-327 granular composites are further…
Ionic size is considered to be an important factor influencing the unit cell volume of manganites with an ABO3 structure. For La1−xSrxMnO3, however, although the average effective ion radius of all cations taken together increases with increasing x, the unit cell volume decreases for x<0.5. In the case of La1−x…
The lattice strain distributions of epitaxial SrTiO3 films deposited on LaAlO3 were investigated by in situ x-ray diffraction at the temperature range of 25–300K, grazing incident x-ray diffraction, and high resolution x-ray diffraction. The nearly linear temperature dependence of the out-of-plane lattice constant of…
Magnetostriction “jump” effect often occurs in ferromagnetic materials. However, in this letter, the jump effect is observed in antiferromagnetic face-centered-cubic austenitic polycrystalline Mn42Fe58 alloy at room temperature. The magnetostriction under an applied field of 1.0T is 169ppm parallel to the field. The j…
The effect of equal-channel angular pressing (ECAP) on the pitting corrosion resistance of anodized Al and Al-Mg alloy was investigated by electrochemical techniques in a solution containing 0.2 mol/L of AlCl3 and by surface analysis. The time required for initiating pitting corrosion of anodized Al was longer with EC…
Doping strongly influences the properties of ferroelectric perovskite materials. One striking difference between donor- and acceptor-doped materials is the transition from “soft” to “hard” ferroelectric behavior. The physical reasons for this phenomenon are still unclear. The authors present measurements of the ferroe…
Raman spectra of ZnS:Cu,Cl powders show a structural transition from hexagonal to cubic and a crystal growth with increasing Cu addition (>400ppm), which is supposed to result from Cu incorporation or CuxS precipitation. The redshift of longitudinal optical mode in ZnS:Cu,Cl with increased amounts of Cu suggest…
Using the first-principles method combined with the anharmonic oscillator model, the electronic, linear, and nonlinear optical properties of four C3N4 polymorphs are investigated. The calculations show that the third-order susceptibilities and nonlinear refractive indices increase with the increase of volume of C3N4 p…
The authors report the existence of one-dimensional and stable formation of ferroelectric monodomain in single crystalline BaTiO3 nanowire. Piezoresponse force microscopy operated in both vertical and lateral modes showed ferroelectric polarization switching along the axial (lateral) direction of nanowire, while the p…
Epitaxial thin films of the ordered ferromagnetic double perovskite La2CoMnO6 have been grown on (001)-oriented SrTiO3 substrates by pulsed laser deposition. X-ray photoemission spectroscopy analysis suggests that the Mn and Co ions are primarily in the 4+ and 2+ valence states. Magnetic measurements indicate the pres…
The β′ phase precipitated in an Mg-2 at%Y (Mg98Y2) alloy aged to a peak hardness condition at 200°C for 336 h has been studied by high-angle annular detector dark-field scanning transmission electron microscopy (HAADF-STEM). The β′ precipitates have an about 20 nm size and definite facets parallel to the (010) plane,…
Transparent conducting Al-doped Zn1−xMgxO thin films were grown on glass substrates by chemical vapor deposition. The resistivity could be lowered to 10−3Ωcm with optical transmittance above 85% in visible regions. The influence of carrier concentration on band-gap shift in Zn1−xMgxO alloys was systematically studied.…
Structural changes of precipitates in an Mg-5 at%Gd (Mg95Gd5) alloy by aging at 200°C and 250°C have been studied by ordinary high-resolution transmission electron microscopy (HRTEM) and high-angle annular detector dark-field scanning transmission electron microscopy (HAADF-STEM). In the early stage of precipitation b…
Cobalt ferrite (CoFe2O4) thin films were epitaxially grown on (001) SrTiO3 and (001) MgO by laser molecular beam epitaxy. Microstructural studies indicate that the CoFe2O4 grown on (001) SrTiO3 with compressive strain are c-oriented island growth mode with rough surface morphology, whereas the films on (001) MgO with…