SPECIFIC HEAT OF UPd2Al3

1993 ◽  
Vol 07 (01n03) ◽  
pp. 38-41 ◽  
Author(s):  
R. J. RADWAŃSKI ◽  
J. J. M. FRANSE
Keyword(s):  
Magnetic Properties ◽  
Energy Level ◽  
Specific Heat ◽  
Ground State ◽  
Exchange Parameter ◽  
State Function ◽  
Hexagonal Symmetry ◽  
Energy Level Scheme ◽  
Schottky Type ◽  
Good Agreement

Particularities in the specific heat of UPd 2 Al 3, a λ-type of peak with a maximum at 14.5 K and a Schottky-type of peak with a broad maximum at 55 K, has been attributed to the 5f-subsystem of the U atoms. The U-5f contribution has been found to be described surprisingly well within a single-ion Hamiltonian that includes the charge multipolar (CMP) interactions and the antiferromagnetic (AF) exchange interaction between the U 3+ ions. The AF exchange parameter and the full set of the CMP parameters associated with the hexagonal symmetry have been evaluated. The energy-level scheme (ELS) of this Kramers ion is constructed. The ground-state function Γ8 of the 5f 3 electrons is highly anisotropic. This state results from higher-order charge multipolar interactions. Magnetic properties resulting from this scheme including the metamagnetic-like transition at 18 T, the strongly-reduced value for the U-ion moment and its field dependence are found to be in good agreement with experimental observations.

SPECIFIC HEAT OF ErNi5 AND DyNi5

1993 ◽  
Vol 07 (01n03) ◽  
pp. 379-382 ◽  
Author(s):  
R. J. RADWAŃSKI ◽  
N. H. KIM-NGAN ◽  
F. E. KAYZEL ◽  
J. J. M. FRANSE
Keyword(s):  
Rare Earth ◽  
Energy Level ◽  
Specific Heat ◽  
Level Scheme ◽  
Exchange Interactions ◽  
Electron Subsystem ◽  
Energy Level Scheme ◽  
A Value ◽  
Schottky Type ◽  
The Rare Earth

The specific heat of DyNi 5 measured on a single-crystalline specimen in the temperature interval from 1.5 K to 250 K has been analyzed in terms of two electronic subsystems. The conduction-electron subsystem is characterized by a value of the Sommerfeld coefficient γ of 36 mJ/K 2 mol . The contribution of the rare-earth subsystem to the specific heat shows a λ-type of peak at T c and above T c a Schottky-type of peak. The rare-earth contribution is well described within a single-ion Hamiltonian that includes the CEF and exchange interactions of the R 3+ ions. The CEF interactions in ErNi 5 and DyNi 5 have been compared and a very similar charge multipolar distribution around the R 3+ ions is found. The energy level scheme of these Kramers ions with J = 15/2 is derived.

Magnetic dipole interactions in dysprosium ethyl sulphate - I. Susceptibility and specific heat between 20 and 1°K

1959 ◽  
Vol 252 (1269) ◽  
pp. 246-259 ◽  
Keyword(s):  
Specific Heat ◽  
Magnetic Dipole ◽  
Ground State ◽  
Optical Rotation ◽  
Dipole Interaction ◽  
Crystal Axis ◽  
Dipole Interactions ◽  
Degenerate Ground State ◽  
Magnetic Ions ◽  
Good Agreement

Measurements have been made of the magnetic susceptibility and the magnetic contributions to the specific heat of dysprosium ethyl sulphate, at temperatures between 20 and 1°K. It is shown that below about 3°K these properties, and also the earlier optical rotation measure­ments of Becquerel et al ., can be accounted for satisfactorily in terms of a doubly degenerate ground state of the magnetic ions, with spectroscopic splitting factors parallel and perpen­dicular to the crystal axis g 1 = 10.8 and g ┴ = 0, together with an unusually strong coupling between the ions arising from magnetic dipole-dipole interaction. The effect of other inter­actions is shown to be small. Because of this, and the extreme anisotropy of the g -tensor, the properties of this substance at very low temperatures (~ 0.1°K) should closely resemble those of a classical Ising model with known, dipolar forces between the ions. At temperatures above 3°K other states of the ions become populated and it is shown that the first of these lies at an energy of (23 ± 3) k , in good agreement with other experiments.

The magnetic properties of praseodymium metal

1963 ◽  
Vol 276 (1364) ◽  
pp. 39-50 ◽  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Simple Model ◽  
Specific Heat ◽  
Field Model ◽  
Hexagonal Symmetry ◽  
Crystal Fields ◽  
Magnetic Specific Heat ◽  
Crystal Field Parameters ◽  
Two Parameter

The magnetic properties of praseodymium metal are interpreted in term s of a simple model suggested by the crystal structure where alternate layers of ions are subjected to crystal fields of face-centred cubic and hexagonal symmetry. The crystal field parameters are found by fitting the magnetic specific heat anomaly, and the variation of the susceptibility with temperature can be explained using a two-parameter molecular field model. The exchange intemaction is predominantly ferromagnetic in sign. The origin of the hyperfine specific heat is discussed, and attributed to interaction effects, though these must be larger than can be accounted for by simple theoretical estimates.

Magnetic properties of a tri-decorated graphene structure: Monte Carlo study

2016 ◽  
Vol 30 (32) ◽  
pp. 1650233
Author(s):  
A. Jabar ◽  
N. Tahiri ◽  
L. Bahmad ◽  
A. Benyoussef
Keyword(s):  
Monte Carlo ◽  
Magnetic Properties ◽  
Phase Diagrams ◽  
Ground State ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Monte Carlo Study ◽  
Magnetic Hysteresis Loops ◽  
Reduced Temperature ◽  
Good Agreement

In this paper, we study the magnetic properties of a tri-decorated [Formula: see text] graphene structure using Monte Carlo simulations (MCS). Indeed, we first elaborate the ground state phase diagrams and then, we found that from [Formula: see text] phases, the only stable configurations are: [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text]. For low reduced temperature values, the partial magnetizations are found to be in good agreement with the corresponding ground state phase diagrams. The corresponding partial susceptibilities show a notable peak around the reduced temperature value 2.0 in the absence of the external magnetic field [Formula: see text] and crystal field [Formula: see text]. To complete this study, we present and discuss the magnetic hysteresis loops.

Thermal and magnetic properties of ferric methylammonium sulphate

1956 ◽  
Vol 237 (1210) ◽  
pp. 404-412 ◽  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Specific Heat ◽  
Magnetic Anomaly ◽  
Ground State ◽  
Magnetic Contribution ◽  
Lattice Contribution ◽  
Magnetic Cooling ◽  
Maximum Value ◽  
Other Substances

The specific heat and magnetic susceptibility of ferric methylammonium sulphate have been measured at temperatures between 0·17 and 20°K. The specific heat has been analyzed into a lattice contribution and a magnetic anomaly. It is shown that the magnetic contribution to the specific heat can be accounted for almost entirely by the Schottky anomaly due to the Stark splittings of the ground state of the Fe 3+ ions, previously determined by Bleaney & Trenam. These splittings are unusually large in this salt, with the result that the specific heat is very large at temperatures near 1°K, reaching a maximum value of 1·1 cal/mole at 0·33°K. The salt should therefore be useful for magnetic cooling experiments in which other substances are to be kept below 1°K for prolonged periods.

Localized canting model for substituted ferrimagnets. I. Singly substituted YIG systems

1970 ◽  
Vol 48 (23) ◽  
pp. 2857-2867 ◽  
Author(s):  
A. Rosencwaig
Keyword(s):  
Experimental Data ◽  
Magnetic Properties ◽  
Statistical Model ◽  
Magnetic Moments ◽  
Exchange Parameter ◽  
New Model ◽  
Model Based ◽  
Curie Temperatures ◽  
Good Agreement

A statistical model based on the concept of localized canting, originally proposed by Geller and coworkers, is developed to account for the magnetic properties of substituted ferrimagnets. This model is used to determine the exchange parameter ratios Jdd/Jdd and Jaa/Jad in YIG systems by evaluating the magnetic moments and Curie temperatures of two classes of singly substituted YIG over the entire substitution range. Good agreement with experimental data is obtained with the physically reasonable exchange parameter ratios of [Formula: see text] and Jaa/Jad *~ 0.07. It is also shown that both the Yafet-Kittel and the Nowik models may be regarded as particular limiting cases of the new model.

Low lying levels in 81Br

1969 ◽  
Vol 47 (20) ◽  
pp. 2255-2259 ◽  
Author(s):  
M. Salomon ◽  
C. Hojvat
Keyword(s):  
Excited State ◽  
Energy Level ◽  
Excited States ◽  
Ground State ◽  
Level Scheme ◽  
Coulomb Excitation ◽  
Transition Probability ◽  
Energy Level Scheme ◽  
First Excited State

Coulomb excitation of Br targets and the reaction 80Se(p,γ)81Br were used to populate the low lying excited states of 81Br and an energy level scheme is proposed. The reduced transition probability from the ground state to the first excited state of 81Br (276 keV) has been measured to be B(E2) = 410 ± 40 e2 f4.

Large scale multi-configuration Hartree-Fock calculation of the hyperfine structure of the ground state of vanadium

Open Physics ◽  
2006 ◽  
Vol 4 (1) ◽  
pp. 42-57
Author(s):  
Oliver Scharf ◽  
Gediminas Gaigalas
Keyword(s):  
Hyperfine Structure ◽  
Ground State ◽  
Large Scale ◽  
Electric Quadrupole ◽  
State Function ◽  
Hartree Fock ◽  
The Core ◽  
Experimental Values ◽  
State Functions ◽  
Good Agreement

AbstractThe hyperfine structure of the ground state of vanadium, 51VI, is calculated in the nonrelativistic framework of the multi-configuration Hartree-Fock approximation. A configuration state function limiting algorithm is used to make the calculations feasible and to study the influence of core, valence and core-valence correlations in detail. The obtained configuration state function space captures the most important orbital correlations within 2%. Further correlations are included through configuration interaction calculation. The atomic state functions are used to evaluate the magnetic dipole hyperfine factor A and the electric quadrupole factor B. It turns out that the ab initio calculation can not capture the core polarization of the 2s shell. It introduces an error that is higher than the Hartree-Fock approximation. However, the detailed correlations being observed suggest the introduction of a wrong correlation orbital due to the algorithm being used. Neglecting this orbital leads to good agreement with 2% deviation from the experimental values for the A factors.

Extensions to the spark spectra of zinc. I. Zinc II and zinc IV

1968 ◽  
Vol 46 (10) ◽  
pp. 1241-1251 ◽  
Author(s):  
A. M. Crooker ◽  
K. A. Dick
Keyword(s):  
Energy Level ◽  
Ground State ◽  
Level Scheme ◽  
Energy Levels ◽  
Spectral Lines ◽  
Energy Level Scheme ◽  
New Energy ◽  
Ground State Doublet

The spectrum of Zn II has been extended to complete the configuration 3d94s(3D)4p′ and 3d94s(1D)4p″. The configurations 3d109f, 3d1010f, and 3d94s(3D)5s′ have been added and a number of levels of the configurations 3d94s(3D)4d′, 3d94s(1D)4d″, and 3d94s(3D)6s′ have been tentatively established. Our list of Zn II lines contains 363 classified lines.Improved wavelength measurements have necessitated a revision of our earlier report on the spectrum of Zn IV. All the energy levels have been shifted slightly with respect to the ground state doublet 3d92D. In addition, 3 of 17 even levels and 10 of 43 odd levels have been changed. The new energy-level scheme results in the classification of 329 spectral lines as compared with 200 lines in the previous report.

The ground state g tensors of LiUF6, NaUF6, and CsUF6

1976 ◽  
Vol 54 (17) ◽  
pp. 1781-1783
Author(s):  
A. F. Leung
Keyword(s):  
Magnetic Properties ◽  
Unpaired Electron ◽  
Ground State ◽  
Electrostatic Charge ◽  
Experimental Measurements ◽  
Charge Model ◽  
Optical And Magnetic Properties ◽  
Good Agreement

The optical and magnetic properties of the 5f unpaired electron in LiUF6, NaUF6, and CsUF6 have been calculated using the electrostatic charge model. The g tensors of the ground state of these compounds show good agreement with experimental measurements.

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