排序方式: 共有44条查询结果,搜索用时 31 毫秒
1.
W. Henggeler T. Chattopadhyay B. Roessli D. I. Zhigunov S. N. Barilo A. Furrer 《Zeitschrift für Physik B Condensed Matter》1995,99(4):465-467
We performed inelastic neutron scattering experiments to determine the dispersion of the Г 6 (1) -Г 6 (2) crystal field excitation in Nd2CuO4. Our results can be very well described within the random phase approximation model. This allows a direct determination of the exchange coupling constants between the Nd ions. The superexchange interactions mediated by the oxygen and copper-oxygen layers are determined to be significantly stronger than the in-plane exchange between the Nd ions. 相似文献
2.
3.
A. G. Smol’nikov V. V. Ogloblichev S. V. Verkhovskii K. N. Mikhalev A. Yu. Yakubovskii K. Kumagai Y. Furukawa A. F. Sadykov Yu. V. Piskunov A. P. Gerashchenko S. N. Barilo S. V. Shiryaev 《JETP Letters》2015,102(10):674-677
The magnetically ordered phase of the CuCrO2 single crystal has been studied by the nuclear magnetic resonance (NMR) method on 53Cr nuclei in the absence of an external magnetic field. The 53Cr NMR spectrum is observed in the frequency range νres = 61–66 MHz. The shape of the spectrum depends on the delay tdel between pulses in the pulse sequence τπ/2–t del–τπ–t del–echo. The spin–spin and spin–lattice relaxation times have been measured. Components of the electric field gradient, hyperfine fields, and the magnetic moment on chromium atoms have been estimated. 相似文献
4.
A. A. Makhnev L. V. Nomerovannaya A. O. Tashlykov S. N. Barilo S. V. Shiryaev 《Physics of the Solid State》2007,49(5):894-899
The temperature dependences of the optical properties and the electrical resistivity for EuBaCo2O5+δ single crystals are investigated. At temperatures below the metal-insulator transition (T MI = 340 K), the electrical resistivity is well approximated by the relationship ρ = ρ0exp(T/T 0)1/4. The optical band gap E g = 0.05 eV for the insulating phase is underestimated as compared to the theoretical value. The specific features in the dispersion of the optical conductivity and the real part of the complex permittivity upon the metal-insulator transition are determined. It is demonstrated that the optical response from charge carriers on the metal side of the metal-insulator transition is caused by the redistribution of the spectral weight of the optical conductivity from the high-energy range to the low-energy range and exhibits a strongly incoherent character. The revealed features are associated with the manifestation of the strongly correlated metallic state. 相似文献
5.
A. G. Smol’nikov V. V. Ogloblichev A. F. Sadykov Yu. V. Piskunov A. P. Gerashchenko S. V. Verkhovskii A. Yu. Yakubovskii S. N. Barilo G. L. Bychkov S. V. Shiryaev 《Journal of Experimental and Theoretical Physics》2011,112(6):1020-1025
The NMR spectra and the decay of a spin echo signal from 51V nuclei in Kagome-staircase Co3V2O8 (CVO) and Ni3V2O8 (NVO) single crystals are measured in the temperature range 30–300 K and a magnetic field H
0 = 20 kOe. The orientation dependences of the 51V NMR line shape are used to determine the electric field gradient (EFG) parameters, namely, quadrupole frequency ν
Q
and asymmetry parameter η. These parameters for NVO and CVO are ν
Q
= 180(10) kHz, η = 0.5(1) and ν
Q
= 130(10) kHz, η = 0.6(1), respectively. A comparison of the results of calculating EFG tensors with a point charge model
and the NMR data indicates that the crystallographically equivalent vanadium atoms in the Ni3V2O8 and Co3V2O8 compounds differ in the EFG axis orientation. M3V2O8 crystals are found to have vanadium positions (V1, V2) with different orientations of the z axis, which specifies the direction of the principal value of EFG (V
zz
): these orientations lie in the bc plane and make an angle of either +51(5)° (V1) or −51(5)° (V2) with axis c. In the temperature range 30–300 K, the EFG tensor components and the local symmetry of the charge surrounding of the vanadium
positions in NVO and CVO oxides are found to change insignificantly. 相似文献
6.
本文利用KDV方程所对应的线性方程解所具有的光滑效应及压缩映像原理,得到了Hirota-Satsuma系统初值问题的局部和整体适定性结果. 相似文献
7.
D. D. Khalyavin S. V. Shiryaev G. L. Bychkov S. N. Barilo S. N. Ustinovich H. Szymczak R. Szymczak P. Allenspach 《Crystal Research and Technology》2003,38(9):748-754
Single crystals of LaMn1−xCoxO3 (0 < x < 1) with distorted perovskite structure have been obtained by the electrodeposition technique at anode from flux melt using Cs2MoO4‐MoO3 binary system as solvent. An investigation of magnetic and electrical properties of the obtained crystals as well as its comparison with those for ceramic samples of the same composition were carried out. A much weaker interplay between magnetic and electrical properties and a smaller ∼8% magnetoresistance were found in the ternary oxide crystals slightly doped by Co on the verge of transition to ferromagnetic state in comparison to the data have been reported for LaMnO3+δ single crystals. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
8.
A. A. Makhnev A. V. Lukoyanov L. V. Nomerovannaya A. A. Shirokov S. N. Barilo G. L. Bychkov S. V. Shiryaev 《Journal of Experimental and Theoretical Physics》2018,126(6):779-783
The anisotropy of the components of the complex permittivity of vanadate Co3V2O8 and Co3V2O8 single crystals in the paramagnetic phase are studied by optical ellipsometry in the spectral region 0.5–5.0 eV. Our experimental results support the weak anisotropy of the optical response detected earlier for axes a and c. The optical properties are also investigated along axis b. The properties of both compounds are compared. The optical spectra of both compounds along axis b are shifted toward low energies as compared to axes a and c. The maximum of the main interband absorption band of Co3V2O8 is shifted toward low energies by 0.25–0.3 eV as compared to Co3V2O8. The electronic structure parameters of both compounds are determined. Optical function spectra are analyzed using the results of ab initio band calculations. 相似文献
9.
The vibronic vapour phase photoacoustic spectrum of Br2 in the wavelength region 505–541 nm (19796–18480 cm−1) has been recorded using microphone as well as pump-probe method. Discrete vibronic bands superimposed on a monotonically
increasing continuum background towards the dissociation limit results from the overlapping B
3Π
0u
/+
← X
1Σ
g
/+
and 1Π1u
← X
1Σ
g
/+
electronic transitions. Vibronic bands originating from υ″=0 have been used to estimate the relative rate of non-radiative relaxation as a function of the excited state B
3Π0u
vibrational quantum number υ′. A comparison with the optical absorption spectroscopy of Br2 leads to the identification of three broad spectral regions between 505 and 541 nm (19796 and 18480 cm−1) on the basis of different non-radiative relaxation processes. 相似文献
10.
A. G. Soldatov S. V. Shiryaev S. N. Barilo V. V. Vashchuk 《Journal of Analytical Chemistry》2000,55(8):791-794
An improved procedure for determining oxygen in single crystals was developed. The procedure was tested on samples prepared
from stoichiometric BaBiO3 by thermal treatment in a controlled medium. The error of the procedure is about 0.5 mol%. 相似文献