NUCLEAR ORIENTATION OF Mn54 IN MnSiF6∙6H2O

1962 ◽  
Vol 40 (10) ◽  
pp. 1417-1422 ◽  
Author(s):  
J. M. Daniels ◽  
D. J. Griffiths

Mn54 was oriented in a single crystal of MiiSiF6∙6H2O, and the anisotropy of emission of γ-rays relative to the trigonal axis of the crystal was measured as a function of temperature in the range 0.06° K to 0.12° K. The anisotropy exhibited the expected I/T3 dependence in this temperature range. From these measurements, a value of −0.034 ± 0.005 cm−1 was deduced for the value of the constant D which occurs in the spin-Hamiltonian [Formula: see text].

1977 ◽  
Vol 32 (7) ◽  
pp. 724-730 ◽  
Author(s):  
R. de Beer ◽  
F. Biesboer ◽  
G. van Veen

Abstract The spin Hamiltonian parameters of 55Mn2+ in cubic ZnS have been determined by means of EPR and central-ion ENDOR, using Ka-band (35 GHz) microwaves. For the first time a value for the spherical electric quadrupole interaction of Mn2+ incorporated in a single crystal has been found. Also the ligand hyperfine interaction and the electric quadrupole interaction of the twelve Zn67 nuclei nearest to Mn2+ have been determined by means of ligand ENDOR.


2009 ◽  
Vol 24 (2) ◽  
pp. 430-435 ◽  
Author(s):  
D. Li ◽  
H.H. Hng ◽  
J. Ma ◽  
X.Y. Qin

The thermoelectric properties of Nb-doped Zn4Sb3 compounds, (Zn1–xNbx)4Sb3 (x = 0, 0.005, and 0.01), were investigated at temperatures ranging from 300 to 685 K. The results showed that by substituting Zn with Nb, the thermal conductivities of all the Nb-doped compounds were lower than that of the pristine β-Zn4Sb3. Among the compounds studied, the lightly substituted (Zn0.995Nb0.005)4Sb3 compound exhibited the best thermoelectric performance due to the improvement in both its electrical resistivity and thermal conductivity. Its figure of merit, ZT, was greater than the undoped Zn4Sb3 compound for the temperature range investigated. In particular, the ZT of (Zn0.995Nb0.005)4Sb3 reached a value of 1.1 at 680 K, which was 69% greater than that of the undoped Zn4Sb3 obtained in this study.


2013 ◽  
Vol 55 (1) ◽  
pp. 235-239 ◽  
Author(s):  
A. V. Inyushkin ◽  
A. N. Taldenkov ◽  
A. V. Gusev ◽  
A. M. Gibin ◽  
V. A. Gavva ◽  
...  

1957 ◽  
Vol 35 (9) ◽  
pp. 1133-1145 ◽  
Author(s):  
J. M. Daniels

The angular distribution of γ-radiation from an assembly of nuclei oriented by the magnetic h.f.s. method can be very much modified by interactions between the radioactive ions and other paramagnetic ions in the crystal. In order to calculate the effect of these interactions, an operator Γ is derived which represents the angular distribution of γ-rays from a radioactive nucleus. The angular distribution at any temperature is given by Spur(Γρ), where ρ is the statistical matrix [Formula: see text], [Formula: see text] being the Hamiltonian for the whole crystal. For a high temperature approximation, ρ is expanded in powers of 1/T. It is found that, for alignment by the magnetic h.f.s. method, the first term which contains interaction parameters is that in 1/T4, and an expression is given for the contribution of interactions to this term.At very low temperatures, perturbation theory is used to estimate the effect of interactions on the lowest nuclear energy state, and hence on the angular distribution of γ-rays. It is found that, if an external magnetic field is applied along a principal axis of the g-tensor of the radioactive ions, interactions have no influence on the angular distribution of γ-rays in the limit of large fields. It is also shown that Bleaney's restriction, that for a successful nuclear orientation experiment the broadening of the levels should be less than the hyperfine splitting, is not necessary in this case.


1969 ◽  
Vol 47 (14) ◽  
pp. 1485-1491 ◽  
Author(s):  
Neil Waterhouse

The specific heat of copper heated in hydrogen at 1040 °C has been measured over the temperature range 0.4 to 3.0 °K and found to be anomalous. The anomaly occurs in the same temperature range as the solid hydrogen λ anomaly which, in conjunction with evidence of ortho to para conversion of hydrogen in the sample, suggests the presence of molecular hydrogen in the copper. The anomaly reported by Martin for "as-received" American Smelting and Refining Company (ASARCO) 99.999+ % pure copper has been briefly compared with the present results. The form of the anomaly produced by the copper-hydrogen specimen has been compared with Schottky curves using the simplest possible model, that for two level splitting of the degenerate J = 1 rotational state of the ortho-hydrogen molecule.Maintenance of the copper-hydrogen sample at ~20 °K for approximately 1 week removed the "hump" in the specific heat curve. An equation of the form Cp = γT + (464.34/(θ0c)3)T3 was found to fit these experimental results and produced a value for γ which had increased over that for vacuumannealed pure copper by ~2%.


Author(s):  
А.И. Дмитриев ◽  
А.В. Кочура ◽  
С.Ф. Маренкин ◽  
E. Lahderanta ◽  
А.П. Кузьменко ◽  
...  

The magnetic anisotropy of needle-like single-crystal MnSb inclusions in the InSb matrix was determined and studied in the temperature range 5 – 350 K. In granular InSb-MnSb samples a power-law dependence of the anisotropy constant K(T) on the saturation magnetization MS(T) is observed in the temperature range 5 – 350 K with an exponent n = 3.2 ± 0.4 in accordance with the theories developed by Akulov, Zener, and Callens.


2021 ◽  
Vol 2057 (1) ◽  
pp. 012048
Author(s):  
N I Matskevich ◽  
V N Shlegel ◽  
A A Chernov ◽  
D A Samoshkin ◽  
S V Stankus ◽  
...  

Abstract The heat capacity of lithium tungstate single crystal (Li2WO4) was measured for the first time in the temperature range of 319-997 K. The experiments were carried out by DSC calorimetry. The Li2WO4 single crystal was first grown by low-temperature-gradient Czochralski technique with weight control. The temperature dependence of Li2WO4 heat capacity in the temperature range 319-997 K was monotonic. According to results of our studies, there were no phase transitions in Li2WO4 in the investigated temperature range.


1990 ◽  
Vol 193 ◽  
Author(s):  
Jin Wu ◽  
Yening Wang ◽  
Yifeng Yan ◽  
Zhongxian Zhao

ABSTRACTThe temperature dependence of the in-plane C11 C22. C12 and C66 modes between 80 and 260 K of superconducting crystals of Bi2Sr2Ca1Cu208 have been obtained via the measurements of ultrasonic-velocities. The anisotropic elasticity in the a-b plane of single crystal Bi2 Sr2Ca1Cu2O8 is manifest. The shear modulus of sound propagation along the [110] with the polarization has been also calculated and shows an overall trend of softening over a wide temperature range above Tc. The shear modulus C6 6 shows three obvious softening minima around 240–250 K, 150 K and 100 K.


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