共查询到20条相似文献,搜索用时 31 毫秒
1.
The 59Co(n, n'γ)59Co reaction has been studied for incident neutron energies ranging from 1.3 to 3.9 MeV. The pulsed-beam time-of-flight technique was employed to discriminate between the inelastically scattered neutrons and the de-excitation γ-rays, which were detected by means of a true-coaxial Ge(Li) detector. Thirty-five levels were identified in this way, and their excitation functions have been extensively compared with the predictions of the statistical theory of the compound nucleus. Possible spin assignements to the levels of 59Co are discussed and compared with the results available from previous works. 相似文献
2.
The 59Co NMR in a CsCoCl3 single crystal has been observed by the spin echo method at 4.2 K. The obtained spectrum is composed of seven distinct lines split by the nuclear-quadrupole interaction. The frequency of the central (± ? ± ) transition 502.08±0.05 MHz corresponds to the hyperfine field of 499.38 ± 0.05 kOe, which agrees well with the calculated value. Due to the interaction of the nucleus with the electronic moment induced by the external field, a shift as large as 18% was observed for the nuclear g-factor. 相似文献
3.
V.N. Nguyen F. Tcheou J. Rossat-Mignod R. Ballestracci 《Solid State Communications》1983,45(2):209-213
Neutron diffraction studies and magnetic measurements on the compounds TbNi2Si2 (1), HoCo2Si2 (2) and TbCo2Si2 (3) revealed a collinear antiferromagnetic order below TN = 10 ± 1 K (1), TN = 13 ± 1 K (2) and TN = 30 ± 2 K (3) with the rare earths moments oriented along the c-axis [m0 = 8.8 ± 0.2 μB (1), m0 = 8.1 ± 0.2 μB (2), m0 = 8.8 ± 0.2 μB (3)] and the corresponding wavevector are . The magnetic structure of the compounds HoCo2Si2 and TbCo2Si2 consists of ferromagnetic layers perpendicular to the c-axis coupled antiferromagnetically (+?+?) while for TbNi2Si2 the ordering within (0 0 1) plane is antiferromagnetic and the planes (0 0 1) are indeed decoupled. 相似文献
4.
V.M. Lebedev A.V. Spassky I.B. Teplov L.N. Fateeva L.Z. Ismail 《Nuclear Physics A》1978,298(2):206-216
The angular distributions of tritons from the (α, t) reaction on 19F, 27Al, 51V and 59Co nuclei corresponding to the (0+) ground states and (2+) excited states in the final nuclei have been measured in the angular range between 15° and 170° at α-particle energies of 25 MeV. For reactions on 27Al and 51V nuclei, the differential excitation functions have also been obtained at different angles of outgoing tritons at Eα from 20 to 25 MeV. The experimental angular distributions are analysed by the DWBA approximation on the assumption of a nucleon stripping mechanism. The analyses of the present results and the data obtained earlier for the (α, t) reaction on the 1 p shell nuclei, A ? 30, reveal that the distinguishing feature of the reaction under study is the presence of backward angle peaks in the reaction cross section, which appear to be associated with exchange processes. For the (α, t) reaction on the heavier nuclei (A > 30), the dominant mechanism is nucleon stripping. 相似文献
5.
From the temperature dependences of the 59Co Knight shift and the nuclear spin-lattice relaxation rate in the exchange-enhanced paramagnetic metal CoSe2, it is shown that the amplitudes of the temperature-dependent spin density fluctuations are saturated at . This fact indicates that there exist local moment type fluctuations above T1. The results obtained from the present NMR investigation are in general accord with the predictions based on the general theory of spin fluctuations in itinerant electron systems developed recently by Moriya and Takahashi. 相似文献
6.
G. Aubert D. Gignoux F. Givord R. Lemaire B. Michelutti 《Solid State Communications》1978,25(2):85-87
In order to confirm the magnetization reorientation in HoCo2, torque measurements have been performed at various temperatures on a spherical single crystal, in the (001) and (011) planes. The easy magnetization direction is the [110] axis at 4.2 K and the [100] axis above 16 K. Furthermore, between 11 K and 16 K, the easy magnetization direction rotates progressively within the (001) plane. These results agree with the magnetization measurements and can be interpreted by a crystal field model. 相似文献
7.
8.
E.C. Reynhardt 《Solid State Communications》1974,15(3):643-645
The chemical shift tensors of 59Co in a single crystal of Co(NH3)6Cl3 at the five nonequivalent cobalt sites were measured at room temperature. The principal axes of these tensors almost coincide with the principal directions of the electric field gradient tensors. Assuming that these directions are parallel to the symmetry axes about which the different Co(NH3)63+ octahedra reorientate, possible reorientation axes of the octahedra at the five nonequivalent sites are proposed. 相似文献
9.
Penelope Schobinger-Papamantellos Ch. Routsi J.K. Yakinthos 《Journal of Physics and Chemistry of Solids》1983,44(9):875-877
We have carried out neutron diffraction on a HoCo2Si2 powder sample at 4.2 K. The magnetic structure of this compound is collinear antiferromagnetic with the holmium magnetic moments parallel to the c-axis of the crystal. The magnetic moment value of holmium is 9.85 μB. The magnetic space group is I4/mm'm' (Sh410128) k = 000 The ordering temperature is tn = 12(1) K. 相似文献
10.
P.R. Locher 《Physics letters. A》1973,42(7):490
A comment is made on a recent paper by Saji and Yamadaya, who erroneously attribute a single cobalt NMR line in Co3S4 to cobalt at the B sites of the spinel lattice. A summary is given of earlier published work which describes cobalt NMR at both A and B sites. 相似文献
11.
The 54Fe(τ, d)55Co reaction has been studied at 25 MeV incident energy with a split-pole spectrometer. About one hundred levels have been observed in 55Co up to 10 MeV excitation energy. Angular distributions have been measured and analyzed with DWBA and Gamow functions as form factors for unbound levels. The 54Fe(τ,dp?)54 reaction has been investigated at 24 MeV incident energy. The angular distributions of the emitted protons were measured in coincidence using method 2 of Litherland and Ferguson, with 0 detection of deuteron groups. Spins, population parameters, branching ratios and proton partial widths for the transitions to the ground and excited states of 54Fe were determined from the analysis of the angular correlation data. The results of these two experiments provide a large number ofspectroscopic properties of unbound proton states and in particular of analog states of 55Fe low-lying levels. The IAS of the ground state of 55Fe is observed to be split between two individual levels. The amplitude of neutron coupling to the first 2+ excited state of 54Fe is obtained for the and low-lying parent statfes in 55Fe. summed spectroscopic factors and the centroid energies of the proton states in 55Co are obtained. A comparison is made with previous (τ, d), (d, p) and (p, p) results. 相似文献
12.
J. Jastrzebski P.P. Singh T. Mróz H.J. Karwowski S.E. Vigdor M. Fatyga 《Physics letters. [Part B]》1984,136(3):153-156
Thick-target recoil ranges of radioactive nuclei produced in 30–200 MeV alpha-particle bombardment of 59Co have been used to deduce the longitudinal momentum transfer per projectile nucleon (p6/A) as a function of residue mass and bombarding energy. The average value of p6/A increases monotonically with bombarding energy and reaches a maximum value of ≈ 160 MeV/c at ≈ 23 MeV/u, and decreases thereafter. The maximum value of p6/A is equal to the incident momentum up to ≈ 23 MeV/u and saturates at a value of ≈ 220 MeV/c beyond this energy. 相似文献
13.
Magnetometric and neutron diffraction studies of polycrystalline NdCo2GE2, ErCo2Ge2 and PrFe2Ge2 compounds were carried out in the temperature range between 4.2 and 300 K. All samples are antiferromagnetic with Néel temperature 26.5, ~ 4.2 and 13 K, respectively. The RECo2Ge2 compounds have collinear antiferromagnetic order of +?+? type. For PrFe2Ge2 a sinusoidal magnetic structure is observed. Magnetic moment is localized on RE atoms only and is equal to that of RE3+ free ion value. In ErCo2Ge2 the magnetic moment of Er atoms is perpendicular to the c-axis, whereas for remaining compounds it is parallel to the c-axis. 相似文献
14.
The anisotropic hyperfine fields of the intermetallic compounds have been studied by the spin echo method and were obtained from the NMR spectra of 59Co nuclei in ThCo5 and YCo5 which have the high anisotropy fields resulting from the orbital moments. The intermetallic compounds, ThCo5.3 and YCo5.3, have been also investigated. 相似文献
15.
The 59Co(d, 3He)58Fe reaction at a deuteron energy of 33.3 MeV was used to populate proton hole states in 58Fe. Angular distributions were measured for the states up to 6 MeV excitation. From DWBA analysis, l-values and spectroscopic factors were extracted. The particle-vibration coupling model was used to interpret the positive-parity states observed in the present experiment as well as the related properties of 58Fe established so far. The model calculation has reproduced rather well the level properties of 58Fe. 相似文献
16.
U. Sennhauser W. Dey H.-J. Pfeiffer H.K. Walter H.S. Pruys F.W. Schlepütz R. Engfer R. Hartmann E.A. Hermes P. Heusi H.P. Isaak W.H.A. Hesselink 《Nuclear Physics A》1982,386(3):447-459
Energy spectra and angular distributions of two coincident charged particles emitted following stopped negative pion absorption in 12C, 59Co and 197Au were measured. Most of the data can be understood within the framework of a pair absorption model including final-state interactions. Ground-state transitions in the missing mass spectra of 4H and 4He deduced from the αα and tα spectra of 12C, respectively, show that reactions involving a large part of the nucleus also occur. 相似文献
17.
F. Pourarian 《Physics letters. A》1979,72(2):175-177
Magnetostriction measurements are reported for TbAl2 below the ordering temperature. Single crystal magnetostriction coefficients are estimated for TbAl2. From the measured data together with the results obtained earlier for TbCo2, it is found that the source of the magnetostriction is the strain-dependent anisotropy of the Tb sublattice. 相似文献
18.
J.K. Yakinthos Ch. Routsi Penelope Schobinger-Papamantellos 《Journal of Physics and Chemistry of Solids》1984,45(6):689-693
Neutron diffraction studies of polycrystalline PrCo2Si2 and TbCo2Si2 compounds were carried out at 4.2 and 293 K. Both samples have collinear antiferromagnetic order below TN(31(1) and 46(1) K for Pr and Tb compound respectively), with their magnetic moments parallel to the c axis. The ordered magnetic moment values of Pr and Tb at 4.2 K (3.19 and 9.12 μB respectively), are close to the saturation value of the free ions. The corresponding magnetic space group Pl4/mnc (Sh410128) is body-anticentered ( refering to Pl cell). 相似文献
19.
The specific heat of HoCo2 has been measured between 1.3 and 5K, a temperature range in which the nuclear specific heat predominates. The magnetic moment of holmium determined from the data is (10 ± 0.2)μB. This value is compared with the values deduced from magnetization and elastic neutron scattering experiments. 相似文献
20.
H. Figiel 《Journal of magnetism and magnetic materials》1982,27(3):303-310
The spin echo NMR spectra of 59Co in R2(Co1-xMnx)17, (R = Y, Gd) measured at 4.2 K are reported. The large shift of resonance lines is observed, that is explained as caused by reorientation of easy axis of magnetisation from easy plane to easy direction (c axis). It is suggested to explain quantitatively the spectra, that only two of four Co sites (9d and 18f) in R2Co17 structure play a dominant role in determining of anisotropy energy and the Co atoms at the 6c sites (“dumb-bell” atoms) give no direct contribution to the anisotropy energy of the compound. The corresponding changes of local anisotropy energy and the orbital part of cobalt magnetic moment characteristic for each of cobalt structural sites are calculated and discussed. 相似文献