Y. Zhuo1)
,
M. Gao1
,
2)and J.Y. Chen1
,
3) 1) Department of Physics
,
Shenyang Normal College
,
Shenyang 110031
,
China2) Institute of Metal Research
,
The Chinese Academy ofsciences
,
Shenyang 110015
,
China 3) International Centerfor Materials Physics
,
CAS
,
Shenyang 110015
,
China
金属学报(英文版)
BiVxSrCaCu2 Oysystem glasses were prepared by using doubleroller quenching method. Thedifferentialthermal analysis was employed to investigate the effect of V doping on glass forming ability( GFA). Theresultsshowedthatthe GFAof Bisystem increases withthein creasing ofthe amountof Vdoping. Thebestatomic ratiofor having both superconductivityandthegreatest GFAwas BiV0 18 CaCu2 Oy .
关键词:
analysis Bisystem glass
,
null
,
null
Physica Status Solidi B-Basic Research
The spin Hamiltonian parameters, g factors and the hyperfine structure constants for Co4+ (3d(5)) and Ir4+ (5d(5)) in SrTiO3 are theoretically studied from the formulas of these parameters for an nd(5) (n = 3 and 5) ion in a tetragonally distorted octahedron with low spin S = 1/2. According to the theoretical analyses, the impurity-ligand bond lengths R-parallel to' parallel to the C-4 axis are found to be larger than the host values R-parallel to based on the phase transition rotation angles phi of the [TiO6](8-) octahedron by the C-4 axis at 4.2 and 77 K, respectively. The elongation of the ligand octahedra in the host may be enhanced in the impurity centers by the Jahn-Teller effect of the nd(5) ions. The theoretical results based on the above local structures show good agreement with the experimental data.
关键词:
electron-paramagnetic-resonance;atomic screening constants;phase-transition;optical-absorption;scf functions;doped srtio3;degrees k;crystals;ions;spectra
QIAO Lijie LIU Rui XIAO Jimei University of Science and Technology Beijing
,
Beijing
,
China
金属学报(英文版)
The effects of stress components on nucleation sites and propagation directions of stress cor- rosion cracks in brass were investigated with specimens under mode Ⅱ and mode Ⅲ loadings. The results indicated that under mode Ⅱ loading,stress corrosion cracks nucleated on the site with maximum normal stress component and propagated along the plane perpendieular to the maximum normal stress,under mode Ⅲ loading,the stress corrosion crack was not evident on the 45°plane due to the general corrosion in aqueous solution with high NH_4OH concentra- tion,while stress corroded in aqueous solution with low NH_4OH concentration, numerous cracks with spacings of 10—150μm were found on the 45°plane with maximum normal stress and no stress corrosion cracks was observed on the plane with maximum shear stress.
关键词:
stress corrosion cracking
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null
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null
,
null
Journal of Applied Physics
Magnetism of bulk La1/3Nd1/3Ca1/3MnO3 with a magnetoresistance ratio as high as -96% in a field of 0.67 T is investigated. Two shoulders are observed on both thermal magnetization curves and magnetization isotherms. A magnetic inhomogeneity model, i.e., simultaneous occurrence of ferromagnetic La-rich domains and nonferromagnetic Nd-rich domains in the compound, is proposed. The model gives a satisfactory explanation for the experimental results. It is argued that a field-induced magnetic transition occurs in the Nd-rich phase and the coexisting La-rich phase can promote the magnetic transition. (C) 1997 American Institute of Physics. [S0021-8979(97)03221-0].
关键词:
ca-mn-o;giant magnetoresistance;transition;la1-xcaxmno3;resistivity;films;phase;field
Japanese Journal of Applied Physics Part 1-Regular Papers Brief Communications & Review Papers
The structures and dielectric properties of Pb(Fe1/2Nb1/2)(1-x)TixO3 (PFNT, x = 0.07 and 0.48) single crystals were investigated using a combination of temperature-dependent dielectric, X-ray diffraction (XRD), Raman, and X-ray absorption fine structure (XAFS) spectra. Detailed structure analyses reveal that the crystal structure of PFNT (x = 0.48) is single-phase tetragonal perovskite, whereas that of PFNT (x = 0.07) is a mixture of rhombohedral and tetragonal phases. The structural differences are found to have significant connections with the dielectric properties in the temperature range of 90-300 K. Both samples exhibit a frequency-dependent dielectric anomaly, arising primarily from the 3d electrons hopping between Fe2+ and Fe3+. The second dielectric anomaly, which is a weak frequency dispersion and observable only for PFNT (x = 0.07), was probably caused by a dipole glass behavior near the morphotropic phase boundary. (C) 2012 The Japan Society of Applied Physics
关键词:
iron;fe;ceramics;region;xanes
Applied Physics Letters
Perovskite-type polycrystalline La1/3Sr2/3FeO3 particles with different sizes (80-2000 nm) were prepared using a simple sol-gel technique. In samples of nanoparticles with a diameter of less than 300 nm, weak ferromagnetism was observed at room temperature, which was attributed to the lattice distortion. The magnetic and specific heat measurements suggest that the charge ordering state was largely suppressed due to the lowering of the particle size, but the charge ordering temperature remained unaffected. (C) 2007 American Institute of Physics.
关键词:
magnetic order;disproportionation;oxides
Journal of Applied Physics
A series of orthorhombic manganites Gd(1-x)Ho(x)MnO(3) (0 <= x <= 0.5) are synthesized. The Ho doping leads to a transition of paraelectric phase into ferroelectric one, making Gd(1-x)Ho(x)MnO(3) multiferroic. It is argued that the enhanced electric polarization originates from the transition of the A-type Mn(3+) anti-ferromagnetic state into the spiral spin order driven by the reduction of Mn-O-Mn bond angle due to the doping. The noncollinear spin order of the A-site Ho(3+) spins at high doping level may also make contribution to the polarization. (c) 2011 American Institute of Physics. [doi: 10.1063/1.3535543]
关键词:
polarization;perovskite
Journal of Applied Physics
We have investigated the electronic transport and transient photovoltaic properties on the La2/3Ca1/3MnO3/Nb (0.05 wt. %):SrTiO3 heterojunction as the temperature increasing from 293 to 623 K. We observed temperature-dependent reversal of the rectifying polarity in the junction with increasing temperature. Temperature also shows effective affection to the transient photosensitivity and response time. On the basis of the results, we propose a possible model involving the change in barrier height and/or width for the carrier conduction at the junction interface induced by the electrochemical migration of oxygen vacancies as the mechanism. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4737256]
关键词:
la0.67ca0.33mno3 thin-films;single-crystals;manganite;electroresistance;interface;oxides
