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1.
《Current Applied Physics》2015,15(11):1545-1548
In type-I multiferroics, where ferroelectricity and magnetism arise from different origins, the explicit measurement of magnetoelectric effect is commonly prohibited due to the weak magnetoelectric coupling. From our investigation of magnetic and dielectric properties in a perovskite PbFe0.5Ti0.25W0.25O3, we have directly demonstrated magnetic-field-driven change of dielectric constant in a highly non-linear fashion. Our result offers a potential utilization of magnetoelectric functionality in type-I multiferroics. 相似文献
2.
3.
Hina Bhargava N. Lakshmi Ram Kripal Sharma K. Venugopalan 《Hyperfine Interactions》2008,183(1-3):155-161
Low temperature Mössbauer and AC susceptibility have been used to study relaxation phenomena in nano-sized particles of Cr0.25Co0.25Zn0.5Fe2O4. From these studies, the energy density constant for this system has been estimated to be 4 x 106 erg/cm3. Cation distribution has also been determined and the observed results are correlated to calculated relaxation times. 相似文献
4.
An optical modulator is designed and fabricated based on a Si0.75Ge0.25/Si/Si0.5Ge0.5 asymmetrical superlattice structure. The device comprises a p-i-n diode made on the asymmetrical superlattice integrated with a 920-μm-long Fabry-Perot (F-P) cavity. Parameters of the rib waveguide are designed to satisfy only the fundamental-TE mode transmission. Here, 65 and 40-pm red shifts of the peak resonant were measured under the applied bias of 2.5 and ?32.0 V, respectively. The analysis shows that, besides the thermal-optical and plasma dispersion effects, the Pockels effect also contributes to such a peak shift. The corresponding calculated effective Pockels coefficient is about 0.158 pm/V.
相似文献5.
The interaction of O2 and N2O are compared on the basal plane of Ru as a function of the coverage of copper. Dissociative N2O uptake (N2O(g) → O(a) + N2(g)) on clean Ru was measured using AES and transient partial pressures. The initial dissociative reaction probability is a steadily declining function of temperature while the saturation uptake of oxygen remains constant from 300–900 K. The saturation oxygen AES signal for N2O chemisorption was one half that observed for O2 chemisorption. The presence of 0.02 monolayers of Cu retards the initial dissociative adsorption of N2O by 40% but has little effect on the total uptake of oxygen. The initial dissociative sticking coefficient for O2 is not retarded significantly by small amounts of copper. Deposition of larger amounts of Cu leads to the completion of a 2D overlayer before growth in 3D begins. Surfaces covered with less than 3 monolayers of Cu exhibit larger O2 sticking coefficients and greater oxygen stability than pure Cu. 相似文献
6.
Hiroyuki Nakano Kaoru Dokko Masanori Hara Yasuhiro Isshiki Kiyoshi Kanamura 《Ionics》2008,14(2):173-177
A novel electrode system composed of three-dimensionally ordered macroporous (3DOM) Li1.5Al0.5Ti1.5(PO4)3 (LATP) and LiMn2O4 was fabricated by the colloidal crystal templating method and sol–gel process. A LATP nanoparticle for the fabrication of
3DOM-LATP was prepared by a sol–gel process. A suspension containing polystyrene (PS) beads and the LATP nanoparticles was
filtrated by using a polycarbonate filter to accumulate PS beads and LATP. The accumulated PS beads had a close-packing structure,
and the void between PS beads was filled with LATP nanoparticles. 3DOM-LATP was obtained by heat treatment of the accumulated
composite. Li–Mn–O sol was injected by a vacuum impregnation process into the macropores of 3DOM-LATP and then was heated
to form three-dimensionally ordered composite materials consisting of LiMn2O4 and LATP. The formation of the composite between 3DOM-LATP and LiMn2O4 were confirmed with scanning electron microscopy and X-ray diffraction method. The prepared composite electrode system exhibited
a good electrochemical performance.
Paper presented at the 11th EuroConference on the Science and Technology of Ionics, Batz-sur-Mer, Sept. 9–15, 2007. 相似文献
7.
Formation mechanism of H2Ti3O7 nanotubes by single-step reaction of crystalline TiO2 and NaOH has been investigated via transmission electron microscopy examinations of series specimens with different reaction times and extensive ab initio calculations. It was found that the growth mechanism includes several steps. Crystalline TiO2 reacts with NaOH, forming a highly disordered phase, which recrystallized into some H2Ti3O7 thin plates. H-deficiency on the top surface leads to an asymmetrical environment for the surface Ti3O2-7 layer. The calculations of the surface tension, elastic strain energy, interlayer coupling energy, and Coulomb force indicated that the asymmetrical environment is the principal driving force of the cleavage of the single sheets of H2Ti3O7 from the plates and the formation of the multiwall spiral nanotubes. 相似文献
8.
D. R. Islamov A. G. Chernikova M. G. Kozodaev A. M. Markeev T. V. Perevalov V. A. Gritsenko O. M. Orlov 《JETP Letters》2015,102(8):544-547
The charge transport mechanism in thin amorphous and ferroelectric Hf0.5Zr0.5O2 films has been studied. It has been shown that the transport mechanism in studied materials does not depend on the crystal phase and is phonon-assisted tunneling between traps. The comparison of the experimental current–voltage characteristics of TiN/Hf0.5Zr0.5O2/Pt structures with the calculated ones provides the trap parameters: thermal energy of 1.25 eV and the optical energy of 2.5 eV. The trap concentration has been estimated as ~1019–1020 cm–3. 相似文献
9.
Weidong Zheng Xiaoping Xu Liangliang Cheng Miao Shui Jie Shu Shan Gao Zhangchao Lu Lin Feng Yuanlong Ren 《Ionics》2013,19(11):1509-1514
A cathode material, 0.5Li2MnO3 0.5LiNi0.5Mn0.5O2, was prepared by citric acid-assisted sol–gel method and its electrochemical performance was investigated. It delivered a charge capacity of 270 mAh g?1 and a discharge capacity of 189 mAh g?1 in the first cycle. With the increase of current density from 14 to 28 mA g?1, the discharge capacity dropped severely to 130 mA g?1. Obviously, the rate capability of the material was inferior to most of the oxide cathode materials. The diffusion coefficient of this material was calculated to be 6.04?×?10?12 cm2 s?1 from the results of cyclic voltammetry measurements. Moreover, diffusion coefficients between 3.13?×?10?12 and 1.22?×?10?10 cm2 s?1 in the voltage range of 3.8–4.7 V were obtained by capacity intermittent titration technique. This, together with the localized Li2MnO3 domains in the crystal structure, may validate the poor rate capability. 相似文献
10.
G.S. Wang Z.G. Hu Z.M. Huang J. Yu F.W. Shi T. Lin J.H. Ma Q. Zhao J.L. Sun X.J. Meng S.L. Guo J.H. Chu 《Applied Physics A: Materials Science & Processing》2004,78(1):119-123
PbZr0.4Ti0.6O3/La0.5Sr0.5CoO3 heterostructures have been grown on Pt/Ti/SiO2/Si substrates by chemical solution routes. Optical properties of the PbZr0.4Ti0.6O3/La0.5Sr0.5CoO3 heterostructures were studied by infrared spectroscopic ellipsometry (IRSE) in the spectral range of 2.5–12.5 m. The optical constants of PbZr0.4Ti0.6O3 and La0.5Sr0.5CoO3 thin films were determined by fitting the IRSE data using a classical dielectric model and a Drude dielectric model, respectively. For PbZr0.4Ti0.6O3 thin films, the refractive index decreases and the extinction coefficient increases as the wavelength increases. For La0.5Sr0.5CoO3 thin films, the refractive index and the extinction coefficient increase as the wavelength increases. The absorption coefficient of La0.5Sr0.5CoO3 thin films is greater than 104 cm-1 for the wavelength range of 2.5–12.5 m. The absorption coefficient of PbZr0.4Ti0.6O3 thin films on a La0.5Sr0.5CoO3/Pt/Ti/SiO2/Si substrate is smaller than that on a Pt/Ti/SiO2/Si substrate by a factor of two. PACS 77.84.Dy; 78.20.Ci; 81.20.Fw 相似文献
11.
Effect of annealing on the phase composition and morphology of Al2O3 formed in a complex electrolyte
I. V. Gasenkova E. V. Ostapenko 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2013,7(3):536-541
The phase composition and morphology of surfaces and cleavages of anodic aluminum oxide (AAO) formed in a complex electrolyte and annealed at 900, 1000, and 1300°C are studied by X-ray diffraction, atomic-force and scanning electron microscopy. It is shown that, depending on the preparation conditions, the following phase states occur: amorphous AAO, the δ phase of Al2O3, and the α phase of Al2O3. The phase transition from the amorphous to the crystalline state under annealing is accompanied by increasing surface area, and the transition from the tetragonal to rhombohedral phase is accompanied by an abrupt decrease in the value of the specific surface and a change in the morphology of the AAO cleaved facets. 相似文献
12.
The influence of size of solvent molecules on the structural and thermodynamic properties of the interface between the electrode and electrolyte, using the solvent primitive model, was studied by grand canonical Monte Carlo (GCMC) simulations. The computer simulation results are compared with those obtained from the modified Poisson–Boltzmann (MPB) theory. The ionic singlet distribution functions show that the solvent molecules of low diameter favour the counter ion adsorption on the electrode. With increasing diameter of the solvent molecules, the mean electrostatic potential increases, while the integral and differential capacitances decrease. The integral capacitance curves obtained by MPB theory are in qualitative agreement with those obtained by the GCMC simulation although the theoretical results are overestimated. 相似文献
13.
G.S. Wang X.J. Meng Z.Q. Lai J. Yu J.L. Sun J.G. Cheng J. Tang S.L. Guo J.H. Chu 《Applied Physics A: Materials Science & Processing》2002,74(5):707-710
La0.5Sr0.5CoO3 (LSCO) films have been grown on Si (100) by a metalorganic chemical liquid deposition (MOCLD) technique using lanthanum acetate,
strontium acetate and cobalt acetate as the starting materials. Subsequent PbZr0.5Ti0.5O3 (PZT) films were deposited onto LSCO films by a modified sol-gel method. Field-emission scanning electron microscopy and
X-ray diffraction analysis show that PZT and LSCO films are polycrystalline and entirely perovskite phase. At an applied electric
field of 250 kV/cm, the Pt/PZT/LSCO capacitor shows no polarization fatigue after 3×109 switching cycles and an internal electric field; the remnant polarization Pr and the coercive field Ec are about 22 μC/cm2 and 73 kV/cm, respectively. The dielectric constant of PZT films is 650 at a frequency of 1 kHz.
Received: 20 February 2001 / Accepted: 6 June 2001 / Published online: 30 August 2001 相似文献
14.
N. I. Mukhurov S. P. Zhvavyi S. N. Terekhov A. Yu. Panarin I. F. Kotova P. P. Pershukevich I. A. Khodasevich I. V. Gasenkova V. A. Orlovich 《Journal of Applied Spectroscopy》2008,75(2):214-218
Luminescent properties of anodic alumina fabricated in anodizing solutions containing oxalic, sulfuric, and phosphoric acids
in addition to those modified by thermal annealing are investigated. Comparison of the obtained data shows that F+-centers are responsible for the luminescence band at 390 nm. The intense photoluminescence band of porous anodic alumina
substrates at 450–500 nm is associated with oxalate anions.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 2, pp. 208–212, March–April, 2008. 相似文献
15.
Gold electrodes with known contact geometries were studied using impedance spectroscopy. From these data it was possible to
determine the specific polarisation conductivity per unit length of three-phase boundary (TPB). The values were found to be
(3÷22)×10−4 S·cm−1 dependent on the electrode history in pure oxygen at 977 °C and 2×10−6 S·cm−1 at 977 °C in “pure” hydrogen (PO2=10−20 atm at 1001 °C). The results are compared with previous data obtained for platinum electrodes. 相似文献
16.
The co-precipitation method can make the materials react uniformly at molecular level and has the advantages of lower polycrystalline synthesized temperature and shorter sintering time. Therefore, it is expected that the mass production of Li1.5Al0.5Ti1.5(PO4)3 (LATP) solid electrolyte would be possible by application of the co-precipitation method for LATP preparation. In this study, an application of the co-precipitation method for a preparation of LATP solid electrolyte is attempted. Crystallized LATP powder is obtained by heating precipitant containing Li, Al, Ti, and PO4 at 800 °C for 30 min. The LATP bulk sintered pellet is successfully prepared using the crystallized LATP powder by calcinating at 1,050 °C. The cross-sectional SEM images show that many crystal grains exist, and the grains are in good contact with each other, i.e., there is no void space. All diffraction peaks of the pellet are attributed to LATP in XRD pattern. The sintered pellet is obtained by calcinating at 1,050 °C, which is more than 150 °C lower than that of conventional method. The LATP solid electrolyte shows a good conductivity which is 1.4?×?10?3 S cm?1 for bulk and 1.5?×?10?4 S cm?1 for total conductivities, respectively. 相似文献
17.
The adsorption of N2O on Ru(001) at ~ 100K has been studied using X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and thermal desorption spectroscopy (TDS). At low exposures, N2O partly dissociates leaving atomic oxygen on the surface and desorbing N2. With increasing N2O exposures, molecular adsorption becomes dominant. He II UPS of the gas phase, solid and monolayer adsorbed molecular N2O are compared. To within experimental error, the peak spacings in all three are the same. The distributions of intensities in the gas and solid phase spectra are the same. In the monolayer spectra, the 7~σ (terminal nitrogen lone pair) orbital intensity is decreased significantly indicating that it is more strongly coupled to the surface than the other valence orbitals. No molecular N2O remains after heating to above 180 K and no detectable amount of dissociated nitrogen appears. Molecularly adsorbed N2O is easily dissociated by an electron beam to give N2(g), NO(g) and O(a). 相似文献
18.
The Ti-doped Ta2O5 thin films (<10 nm) obtained by rf sputtering are studied with respect to their composition, dielectric and electrical properties. The incorporation of Ti is performed by two methods - a surface doping, where a thin Ti layer is deposited on the top of Ta2O5 and a bulk doping where the Ti layer is sandwiched between two layers of Ta2O5. The effect of the process parameters (the method and level of doping) on the elemental distribution in-depth of the films is investigated by the time of flight secondary ion mass spectroscopy (ToF-SIMS). The Ti and Ta2O5 are intermixed throughout the whole thickness but the layers are very inhomogeneous. Two sub-layers exist in all the samples — a near interfacial region which is a mixture of Ta-, Ti-, Si-oxides as well as TaSiO, and an upper Ti-doped Ta2O5 sub-layer. For both methods of doping, Ti tends to pile-up at the Si interface. The electrical characterisation is performed on capacitors with Al- and Ru-gate electrodes. The two types of MIS structures exhibit distinctly different electrical behavior: the Ru gate provides higher dielectric permittivity while the stacks with Al electrode are better in terms of leakage currents. The specific metal-dielectric reactions and metal-induced electrically active defects for each metal electrode/high-k dielectric stack define its particular electrical behavior. It is demonstrated that the Ti doping of Ta2O5 is a way of remarkable improvement of leakage characteristics (the current reduction with more than four orders of magnitude as compared with undoped Ta2O5) of Ru-gated capacitors which originates from Ti induced suppression of the oxygen vacancy related defects. 相似文献
19.
This study is focused on the influence of impurities and electrode morphology on cyclic voltammograms (CV) of one of the most prominent solid state electrode systems, Pt(O2)|YSZ, exemplifying the difficulties in unequivocal interpretation of CV in the solid state in general. By investigating differently prepared electrodes—either by Pt paste or pulsed laser deposition (PLD)—with and without an Si containing additive, the impact of both effects can be separated. For characterisation of the sample SEM, XRD, EDX, Tof-SIMS, XPS, and XPEEM have been used. We demonstrate that the presence of impurities can change the shape of CV and even cause peaks, a fact which has not been considered so far. The processes which theoretically can cause a CV peak in the electrode system Pt(O2)|YSZ are discussed. We reconsider the information unambiguously obtainable from CV studies, and we comment on the controversial questions of the formation of interface Pt oxide and the appearance of spillover oxygen in CV studies. A compact commented survey of literature on CV studies of the system Pt(O2)|YSZ is given. 相似文献
20.
A conductive material, Pb2Ru2O7-x (PRO), containing Pb in a cubic structure was introduced into a Pt/PZT interface in an attempt to improve the ferroelectric properties of PZT films. PRO and PZT films were prepared by rf magnetron sputtering and chemical solution deposition, respectively. The resistivity of PRO thin films in a hybrid-type electrode (PRO/Pt) structure was approximately 35–45 μΩ·cm and the surface roughness remained constant with increasing annealing temperature. The PRO interlayers suppressed the loss of Pb in PZT layers by diffusion to the Pt/PZT interface. The increase in remanent polarization was largely dependent on the PRO interlayers inserted at the bottom-Pt/PZT interface rather than at the top-Pt/PZT interface. In addition, the leakage-current behavior of PZT films in a sandwich structure was improved substantially compared to the case of PRO interlayers only at the bottom-Pt/PZT interface. Thus, the PRO interlayers play an important role in improving the ferroelectric properties of PZT thin films for use in nonvolatile memory device applications. PACS 68.55.-a; 73.40.Rw; 73.61.Ng; 77.55.+f; 81.15.Cd 相似文献