共查询到20条相似文献,搜索用时 31 毫秒
1.
Y. Kohori Y. Yamato Y. Iwamoto T. Kohara 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,18(4):601-604
We have carried out 115In nuclear quadrupole resonance (NQR) measurements in CeRhIn5. At ambient pressure, CeRhIn5 undergoes an antiferromagnetic AF phase transition at K. The 115In NQR spectrum has shown the appearance of a small internal field in the direction perpendicular to the tetragonal c-axis. With application of a hydrostatic pressure, the AF state is suppressed and the superconductivity appears just above
the critical pressure (P
= 17 kbar). The nuclear spin lattice relaxation rate 1/T1 of 115In measured at P
= 27 kbar indicates the occurrence of the superconductivity in the nearly AF region. In the superconducting state, 1/T1 has no Hebel-Slichter coherence peak just below of 2 K and has a power law T-dependence (T3) down to 300 mK. This is consistent with anisotropic superconductivity, with line nodes in the superconducting energy gap:
non-s-wave superconductivity occurs in CeRhIn5.
Received 5 July 2000 相似文献
2.
Abstract The emission spectra for LaOBr : Eu were measured at pressures up to 13 GPa and room temperature. The pressure dependences of levels of 7F0,1,2,3,4 and 5D0,1,2 are given. The crystal field parameters Bk q were computed by fitting the experimental levels. The strength of crystal field decreases with increasing pressure. A brief discussion on the observed phenomena is presented. 相似文献
3.
An investigation on the magneto-optic properties of terbium gallium garnet under high magnetic field
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The superexchange interaction on a magnetic ion may be represented by an effective field Hm = $\lambda$M in some paramagnetic materials, here λ is the coefficient of effective field and M = $\chi$He with $\chi$ being the magnetic susceptibility and He being the applied field. The variation of the equivalent $\lambda_{\chi}$with the dynamic applied field is given and the crystal field-splitting levels of the excited configuration 4f75d1 of the Tb3+ ion are calculated in the Tb3Ga5O12. By means of the effective field Hm and the applied field He, the Faraday rotation of Tb3Ga5O12 at 6 K and 41 K, under the high magnetic field and at 0.63 μm wavelength, are presented. Our calculated results are in agreement with the experimental data. 相似文献
4.
R. Ashby J.J. Clarke W.A. van Wijngaarden 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(3):327-331
6Li 32D
3/2, 5/2
states were studied using a diode laser to first excite the 2P
3/2
state and a dye laser to populate the 32D
3/2, 5/2
states. The dye laser was modulated by an electro-optic modulator and intersected an atomic beam that passed through a field
free region and subsequently through a uniform electric field. A value of 1084.24±0.20 MHz was found for the 32D fine structure splitting. The scalar and tensor polarizabilities were determined to be α
(3D
3/2
) = - 3.753±0.015, α
2
(3D
3/2
) = 2.893±0.017, α
(3D
5/2
) = - 3.772±0.008 and α
2
(3D
5/2
) = 4.058±0.013 MHz/(kV/cm)2.
Received 26 September 2002 / Received in final form 22 January 2003 Published online 11 March 2003
RID="a"
ID="a"e-mail: wlaser@yorku.ca 相似文献
5.
Noritaka Kuroda Yasuo Oeda Giyw Kido Masayasu Takeda Yuichiro Nishina Yasuaki Nakagawa 《高压研究》2013,33(1):65-66
Abstract The magneto-optical spectra of the R1 and R2 lines of Cr3+ ions in alexandrite have been measured under hydrostatic pressures and magnetic fields up to 6 GPa and 15 T, respectively. The spins of the excited states, 2E, have the Heisenberg-type characters at atmospheric pressure, though the g-values are anisotropic with the values between 1.3 and 2.0. The g-values for the direction parallel to the α-axis remain unchanged with increasing pressure, while for the directions normal to the α-axis they are reduced appreciably. The fine structure parameters of spins in the ground state, 4A2, exhibit quite a similar behavior. The R1-R2 splitting is reduced also by pressure. These properties are the evidences that the spins of the 2E states become of the king-type under pressures above about 15 GPa. The mechanism of such the change of spin character is discussed quantitatively on the basis of a crystal field model. 相似文献
6.
J. Li C.H. Sow X.S. Rao C.K. Ong D.N. Zheng 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,32(4):471-476
In this research, c-axis oriented epitaxial anatase TiO 2 thin films were grown on SrTiO 3 (100) substrates using a ceramic Ti 0.95 Co 0.05 O 2 target by Pulsed Laser Deposition (PLD). The film growth processes were monitored by reflective high energy electronic diffraction (RHEED). Microstructure, conductivity, and magnetism of these doped films are found strongly affected by the oxygen pressure and substrate temperature Ts. Grown at a Ts around 750 ° C in an oxygen pressure of 0.2 mbar, the dopants are found existing as oxide inclusions. The doped film thus behaves as an insulator and shows diamagnetism in a magnetic field parallel to the film surface. However, in the doped film grown at a reduced temperature of 630 ° C in a vacuum, no impurity phase can be identified. The film shows a saturated magnetic moment of 0.16μ B / Co and a fairly good conductivity at room temperature. It is then concluded that nonequilibrium growth at lower temperatures in vacuum is essential for a high solubility of Co in the TiO 2 lattice and thus the ferromagnetism. 相似文献
7.
Summary Chromium doped single crystals of Forsterite where investigated directly under the influence of uniaxial pressure in situ by ESR. The two Cr3+ centres M1 and M2 exhibit distinct response to the action of pressure on the crystal as a whole. The pressure effects are manifested in remarkable changes of the line width of the fine structure transitions. Uniaxial pressure in the MPa range induces nearly symmetrical distribution of distortions of the coordination polyhedra of the Cr3+ centres accompanied by reorientation effects. 相似文献
8.
Abstract Amorphous, ferromagnetic, invar like, Fe60 Mn20 B20 alloy has been investigated. Two kinds of experiments were carried out for this alloy. The first, using high pressure technique, revealed the influence of pressure on B(H) dependencies within the wide range of temperature under pressure of 0.5 GPa. From the magnetization curves obtained during these experiments the decrease of spontaneous magnetization caused by applied pressure 0.5 GPa at temperature -180°C has been calculated at the rate about 7 10?11T/Pa. In the second kind of experiments the measurements of volume magnetostriction up to 720 kA/m magnetic field intensity have been done. Volume magnetostriction coefficient at temperature 77.4 K has been determined to be about 2 10?11 [A/m]?1. 相似文献
9.
M. W. Evans 《Foundations of Physics Letters》1995,8(1):63-71
It is shown that the longitudinal, magnetic flux density,B
(3)
, of vacuum electromagnetic radiation can be accommodated rigorously within Noether's theorem, which relates fundamental spacetime symmetries to fundamental conservation laws. This demonstration linksB
(3)
to the canonical energy-momentum tensorT
µv that appears in Einstein's field equations of general relativity. Thus,B
(3)
provides a link between electromagnetism and gravitation which might eventually lead to an unified understanding of field theory. 相似文献
10.
A. Wahl V. Hardy C. Martin Ch. Simon 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,26(2):135-140
The Pr
1-x
CaxMnO3 system exhibits a ferromagnetic insulating state for the composition range x
? 0.25. A metallic ferromagnetic state is never realized because of the low hole concentration and the very small averaged A-site
cation radius. In the present study, the nature of the magnetic excitations at low temperature has been investigated by specific
heat measurements on a Pr
0.8
Ca0.2MnO3 single crystal. The decrease of the specific heat under magnetic field is qualitatively consistent with a suppression of
ferromagnetic spin waves in a magnetic field. However, at low temperature, the qualitative agreement with the ferromagnetic
spin waves picture is poor. It appears that the large reduction of the specific heat due to the spin waves is compensated
by a Schottky-like contribution possibly arising from a Zeeman splitting of the ground state multiplet of the Pr3+ ions.
Received 21 May 2001 and Received in final form 14 December 2001 相似文献
11.
N.A. Babushkina L.M. Belova E.A. Chistotina O.Yu. Gorbenko A.R. Kaul B. Güttler K.I. Kugel 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,19(3):409-415
The effect of
16
O
→
18
O isotope substitution on electrical resistivity, magnetoresistance, and ac magnetic susceptibility was studied for La0.35Pr0.35Ca0.3MnO3 epitaxial thin films deposited onto LaAlO3 and SrTiO3 substrates. For the films on LaAlO3, the isotope substitution resulted in the reversible transition from a metal-like to insulating state. The applied magnetic
field ( H
≥ 2
T) transformed the sample with 18O back to the metallic state. The films on SrTiO3 remained metallic at low temperatures for both 16O and 18O, but the shift of the resistivity peak corresponding to onset of metallic state exceeded 63 K after
16
O
→
18
O substitution. The temperature dependence of both resistivity and magnetic susceptibility was characterized by hysteresis,
especially pronounced in the case of the films on LaAlO3. Such a behavior gives certain indications of the phase separation characteristic of interplay between ferromagnetism and
charge ordering.
Received 11 February 2000 and Received in final form 13 September 2000 相似文献
12.
Abstract Luminescence spectra from Eu3+ ion in C-type Eu2O3 under high pressures have been obtained. The spectral shifts can be used to study the effect of pressure on the spin-orbit and the Coulomb interactions of the 4f electrons, which are correlated with expansion of the 4f-electron wave functions. This expansion with the application of pressure results in both the variation of the electronegativity and radius of the Eu3+ ion and, ultimately, the phase transformation from C-to B-type Eu2O3. Therefore, core 4f-electrons can thus be thought of as quasivalence electrons. 相似文献
13.
Abstract Luminescence spectra from Eu3 + ion in B-type (monoclinic) 2O3 powder have been recorded at room temperature as a function of pressure using a diamond anvil cell. Changes in the spectral pattern of the Eu3 + ion emission at about 4 GPa indicated that a phase transition to the A-type (hexagonal) structure had taken place. Upon release of the applied pressure, the B-type structure was regained with hysteresis. The spectral shifts with pressure have been used to study the effect of pressure on the spin-orbit interaction of the 4f electrons in the Ed + ion. The relationship between the relative changes in the spin-orbit coupling constant, ζ4f, and the volume accompanying the phase transition is also discussed. 相似文献
14.
V. P. Glazkov B. N. Savenko V. A. Somenkov D. V. Sheptyakov S. Sh. Shilstein 《高压研究》2013,33(3-6):201-207
Abstract The crystal structure of Nd2CuO4 has been studied by neutron diffraction at pressure up to 5 Gpa. The volume compressibility value was determined as 5·6·10?3/Gpa. The decrease of positional parameter of neodymium at high pressure has been observed. This structural change is explained by pressure induced neodymium ions charge increase. 相似文献
15.
This paper discusses the field and temperature dependences of the shift in position of EPR signals in an external electric
field, which is linearly related to the polarization in the paraelectric phase of Pb5Ge3O11:Gd3+.
Fiz. Tverd. Tela (St. Petersburg) 39, 1643–1644 (September 1997) 相似文献
16.
Abstract Fluorescence from Nd3+ in LaCl3 is measured at 100 K under pressures up to about 10 GPa. The observed variations of the energy levels are used for the evaluation of crystal field parameters. The pressure-dependence of these parameters is compared with the previous results on Pr3+ in LaCl3. 相似文献
17.
Abstract Embedded cluster calculations performed on both ground (4A2g) and excited (4T2g) states of substitutional Cr3+ in halide elpasolites account successfully for the pressure dependence of photoluminescence spectra. 相似文献
18.
A. Podlesnyak Th. Strässle A. Mirmelstein A. Pirogov R. Sadykov 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(4):547-552
Neutron powder diffraction was employed to study the pressure effect on the magnetic transition in the pseudobinary Laves-phase
compound Er0.57Y0.43Co2 and to determine the magnetic moments of the Er- and Co-subsystems. Our studies reveal that the onset of long-range magnetic
order for both the localized 4
f (Er) and itinerant 3
d (Co) electron moments appears at about the same temperature at ambient pressure. The pressure effect on Tc is found to be negative and equal for both sublattices, namely
T
c
/
p
∼ - 0.4 K/kbar. The values of the magnetic moments of the Er and the Co ions are found
= 5.40±0.15μ
B
/atom,
= 0.50±0.07μ
B
/atom and 5.35±0.15μ
B
/atom, 0.37±0.09μ
B
/atom, for p
= 0 and 6 kbar, respectively. Our experimental results give evidence for short-range magnetic order formation at temperatures
already above Tc and for a coexistence short- and long-range order below Tc down to 4 K.
Received 20 December 2001 / Received in final form 12 June 2002 Published online 31 October 2002
RID="a"
ID="a"e-mail: andrew.podlesnyak@psi.ch 相似文献
19.
VLADIMIR I. MAKAROV 《Molecular physics》2013,111(3):867-878
Phosphorescence excitation spectra of the ã3B1← [Xtilde]1A1 transition of SO2 were measured in the absence and presence of a magnetic field (B = 0?44 T2, P(SO2) = 0?7 Torr). The absorption and phosphorescence excitation spectra of the ã3B1← [Xtilde]1A1 transition of SO2 measured in the absence of a magnetic field show that the relative intensity of the bands of the phosphorescence excitation spectrum is smaller than the relative intensity of the corresponding bands of the absorption spectrum beginning with the (0, 2, 0) band. In the presence of a magnetic field, the intensity of the phosphorescence excitation band falls, for νexc> 26400 cm-1. Under the direct excitation of the ã3B1← [Xtilde]1A1 transition, the dependence of the magnetic quenching of the SO2 phosphorescence on the excitation frequency (νexc) was studied at P(SO2) = 0?7 Torr and B = 0?44 T. The dependence of the magnetic field effect on νexcshows that only the vibrationally excited levels of the ã3B1 state are sensitive to an external magnetic field. The magnetic field strength and the pressure dependence of the magnetic field effects were studied under indirect excitation of the ã3B1← [Xtilde]1A1 transition at λexc = 308 nm. The magnetic field and the pressure dependence were investigated for pure SO2 and for SO2 + RH (RH n-C5H12) mixtures. It was found that the magnetic field effect was saturated at B ? 0?25 T. The saturation value (Gr = l(0?3 T)/l(0)) increases with increasing gas pressure. The magnetic field, the pressure and the excess vibrational energy (νexcess) dependence of the magnetic quenching of SO2 phosphorescence show that the data observed can be explained by an indirect mechanism within the framework of a low level density approximation. 相似文献