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1.
The electric field gradient eq at Os nuclei in Os and Re single crystals has been determined by Mössbauer transmission experiments with the 137 keV resonance in 186Os as -4.5 (3) × 1017 V/cm2 and - 3.8 (3) × 1017 V/cm2, respectively. 相似文献
2.
3.
O. Häusser D. Ward T. K. Alexander H. R. Andrews W. J. L. Buyers H.-E. Mahnke J. F. Sharpey-Schafer P. Skensved M. L. Swanson P. Taras 《Hyperfine Interactions》1980,8(1-3):271-281
We have examined the temperture dependence of the efg for GdGd above the Curie point. Using anI
=10+ isomer in144Gd as a probe nucleus, we find a weakT
3/2 dependence withB=(1.5±0.4) 10–5 K–3/2. The absolute value of the efg at 332 K was measured by Coulomb excitation of 2+ states in156, 158, 160Gd, yielding |eq(332 K)|=(3.43±0.14) 1017 V/cm2. A possible small deviation from theT
3/2 temperature dependence of the efg for ferromagnetic Gd is discussed. 相似文献
4.
M. D. Svoren E. F. Zganjar I. L. Hawk 《Zeitschrift für Physik A Hadrons and Nuclei》1975,272(2):213-217
The level structure of188Os has been investigated following the decay of 17h188Re. The energies and relative intensities of 41 gamma rays were determined using large volume high resolution Ge(Li) detectors. The decay was observed to populate the 0+ states at 1478 and 1704 keV which were recently observed in (p, t) reaction studies. Additional states at 1414 and 1843 keV were also observed in the decay. 相似文献
5.
The magnetic hyperfine fieldH
hf and the electric field gradientV
zz at181Ta impurties in metallic Gd were determined by time differential perturbed angular correlation measurements with the 133 keV K-conversion electron 482 keV -cascade of181Ta. The sources for these measurements were prepared by implantation of radioactive181Hf ions into Gd. The results are: |H
hf(TaGd; 77 K)|=285(14)kG, and |V
zz(TaGd; 330 K)|=5.32(15)·1017V/cm2. The value ofH
hf fits well into the systematics for 5d impurities in Gd and indicates a positive core polarisation contribution, which is expected if the conduction electrons of Gd have to a large extent d-character. The electric field gradients of the 5d impurities in Gd are not consistent with a proportionality between the ionic and the electronic contribution. 相似文献
6.
L. A. Mendoza-Zélis A. G. Bibiloni M. C. Caracoche A. R. Lopéz-García J. A. Martínez R. C. Mercader A. F. Pasquevich 《Hyperfine Interactions》1977,3(1):315-320
The electric field gradient EFG in hafnium pyrovanadate has been measured at Hf sites at different temperatures with the time-differential perturbed angular correlation method. The results obtained show the existence of a phase transition around 110°C. 相似文献
7.
T. Butz 《Physics letters. A》1973,46(3):231-233
A uniform, axially symmetric electric field gradient at 181Ta in hcp Y of |eq| = (5.9 ± 0.3) × 1017V/cm2 at 300 K, increasing by 11% upon cooling to 4.2 K, was found using the time differential perturbed angular correlation technique. 相似文献
8.
The electric field gradient in ruthenium metal was studied between 15 K and 863 K. In contradiction to a recently proposed theory [1] the EFG was found to decrease with increasing temperature. 相似文献
9.
Electric field gradient (EFG) in scandium metal has been evaluated at temperatures 11 K and 293 K using band wave functions
determined in the temperature dependent model potentials. The results of net EFG obtained are −3.756×1013 esu/cm3 and −8.009×1013esu/cm3 at 11 K and 293 K respectively. The agreement with available experimental result is reasonably good. 相似文献
10.
By use of low temperature nuclear quadrupole orientation the quadrupole coupling constant of69mZn in a Zn single crystal has been determined asv
Q=eQV
zz/h=–28(3) MHz.A positive sign forV
zzat the nuclear site of Zn in Zn is deduced. The half-life of69mZn has been remeasured asT
1/2=13.756 (18)h. 相似文献
11.
V. Naicker A. Bartos K. P. Lieb M. Uhrmacher T. Wenzel D. Wiarda 《Hyperfine Interactions》1993,80(1-4):965-970
The electric field gradient (efg) of111Cd in polycrystalline V2O5 was studied using perturbed angular correlation (PAC) spectroscopy, with the111In activity ion-implanted at 400 keV. Between the individual steps of an isochronal annealing program, a distinct efg (v
Q
1=88.1(3) MHz, 1=0.62(2)) was recorded the contribution of which increased with annealing temperature up to 74% at 870 K. Corresponding X-ray analysis of inactive V2O5 samples, which underwent the same annealing treatment, proved that the sample always stayed as V2O5. Since V2O5 has only one equivalent cation site, it is concluded that this efg belongs to111Cd at this site. Oxidation of a vanadium foil atT=675 and 800 K at
=200 mbar also yielded this efg. From PAC measurements in VO2, two well-defined efg's were found above and below the metal-semiconductor transition at 340 K, which are tentatively attributed to the monoclinic and the tetragonal phase.Supported by Deutsche Forschungsgemeinschaft and DAAD.On leave from the University of Durban-Westville, South Africa. 相似文献
12.
13.
E. N. Kaufmann 《Hyperfine Interactions》1981,9(1-4):219-233
14.
M. H. Rafailovich O. C. Kistner E. Dafni A. W. Sunyar M. Mohsen S. Vajda G. D. Sprouse 《Hyperfine Interactions》1983,15(1-4):283-287
The method of perturbed angular distributions was used to measure the temperature dependence of the electric field gradient in Er single crystal for 98 KT156 K. The I=11– isomer in Er154) was used as a probe. 0 increases monotonically for 98 KT259 K and then decreases. A possible cause for this effect may be short range interactions between the f electrons above the Neel point.Visitor from the Weizmann Institute, Rehovoth, Israel. 相似文献
15.
Danny G. Chambaere Eddy De Grave Rudy L. Vanleerberghe Robert E. Vandenberghe 《Hyperfine Interactions》1984,20(4):249-262
The temperature behaviour of the hyperfine parameters of iron in paramagnetic chlorine containingΒFeOOH is studied by57Fe Mössbauer spectroscopy. Applying external magnetic fields, the sign and asymmetry parameterη of the electric field gradient (EFG) at the compound's two iron sites is determined. It is shown that an external field enhances the distributive character of the hyperfine parameters. Finally, heat treatment experiments allow new data on the nature of both iron coordination types to be presented. 相似文献
16.
The electric quadrupole interaction at iodine implanted in zinc and cadmium single crystals is investigated, using the - perturbed angular correlation technique. The results show that the implanted129Te and132Te isotopes occupy two well-defined sites, identified by the electric field gradient parameters. One fraction of the impurities is substitutionally implanted, witheq
zz=–1.49(9)1018 and –1.58(15)1018V/cm2, in Zn and Cd respectively. The other fraction is identified as an impurity-divacancy configuration with |eq
zz
|=3.81(8)1018V/cm2; =0.72(4) for Zn and |eq
zz
|=3.55(11)1018V/cm2; =0.53(13) for Cd. The electronic enhancement in the electric fieldgradient at the substitutional site equalsK=–0.66 and –0.56 respectively and follows the empirical trend ofK versus the impurity valence for the s-p elements in Zinc. 相似文献
17.
E.N. Kaufmann 《Journal of Physics and Chemistry of Solids》1973,34(11):2025-2028
Using the time-differential perturbed-angular correlation technique, we have observed the nuclear electric quadrupole interaction at 181Ta (482 keV) as an impurity in the refractory compound HfB2. The measured interaction frequency is νQ=730±5 MHz which corresponds to an electric field gradient of |eq|=(1·19±0·05)×1018 V/cm2 at room temperature. By considering a second measurement at 4·2°K, which yields the same results as above, and by comparison with available results for Hf in HfB2, we conclude that the d-electron density of states at the Fermi level is quite small in agreement with trends observed by others. 相似文献
18.
The electric field gradients (EFGs) at different probe nuclei in Ti and Re hosts are compared with the predictions of the conduction electron charge shift model. It is found that this model is successful in predicting the sign and, to a zero-order approximation, the magnitude of the EFG when the localized d-contributions are small and the universal correlation is obeyed. 相似文献
19.
The variation of the NQR frequency 75vQ for arsenic metal has been measured at 195 and 295 K for pressures up to 2 kbar and at atmospheric pressure between 77 and 525 K. The data are compared with those for other metallic elements. 相似文献
20.
W. Körner W. Keppner T. Klas B. Lehndorff-Junges G. Schatz 《Hyperfine Interactions》1983,16(1-4):993-996
The electric field gradient at indium surfaces was studied with111In PAC-probes as a function of temperature. The surface field gradient was determined to be temperature independent up to 100 K and the fraction of111In surface sites shows a pronounced annealing behaviour between 150 K and 250 K. 相似文献