Estimation of spin transfer parameters through the anisotropic supertransferred hyperfine interaction

1985 ◽  
Vol 63 (5) ◽  
pp. 557-559
Author(s):  
M. E. Ziaei
Keyword(s):  
Hyperfine Interaction ◽  
Neutron Scattering ◽  
Configuration Interaction ◽  
Reasonable Agreement ◽  
Hyperfine Interactions ◽  
Interaction Model ◽  
Covalent Bonding ◽  
Spin Transfer ◽  
Scattering Data ◽  
Transfer Parameters

Using the experimental transferred and anisotropic supertransferred hyperfine interactions, with the configuration interaction model of covalent bonding for the linear bonds of M2+(3dσ)–F−(2pσ)–Cd2+(4pσ) and M2+(3dπ)–F−(2pπ)–Cd2+(4pπ) existing in crystals of CsCdF3: M2+ (where M = Mn or Ni), suggests that fσ, the σ-type spin transfer parameter for the Mn2+–F− bond, is about 3.1%. This value is much larger than estimates from neutron scattering data, although it is in reasonable agreement with the works of Ziaei and Owen, and Rinneberg and Shirley.

The effect of core electrons on the spin transfer parameters

1982 ◽  
Vol 60 (5) ◽  
pp. 636-639 ◽  
Author(s):  
M. E. Ziaei
Keyword(s):  
Hyperfine Interaction ◽  
Electron Distribution ◽  
Spin Transfer ◽  
Unpaired Spin ◽  
Core Electrons ◽  
Transfer Parameters

ENDOR measurements and covalency arguments have been used to investigate the electron distribution in CsCdF3 crystals containing Mn2+ and Ni2+. The bond structure is of the form M—F−—Cd2+ (M = Mn2+ or Ni2+) and the measured isotropic supertransferred hyperfine interaction (sthfi) at the Cd site is related to the unpaired spin fraction fσ in the 2pσ orbital of F− by three different theoretical approximations. In these three methods it is assumed that [Formula: see text] orbital of the 3d ion, and the 2pz orbital of the F− ion make eovalent bonds with the (4s), (3s,4s,5s), and (1s,2s,3s,4s,5s) sets of orbitals of the Cd2+ ion respectively. The results show that cadmium core s electrons make important contributions to the isotropic sthfi. However, it seems that fσ values obtained are fairly insensitive to the approximations used.

Hyperfine interactions in the J = 5 states of 147Sm and 149Sm

1968 ◽  
Vol 46 (22) ◽  
pp. 2499-2507 ◽  
Author(s):  
R. G. H. Robertson ◽  
J. C. Waddington ◽  
R. G. Summers-Gill
Keyword(s):  
Hyperfine Interaction ◽  
Magnetic Dipole ◽  
Configuration Interaction ◽  
Hyperfine Interactions ◽  
Electric Quadrupole ◽  
Dipole Interaction ◽  
Electric Quadrupole Interaction ◽  
Magnetic Dipole Interaction ◽  
Ground Term ◽  
Hyperfine Constants

The hyperfine interaction constants Ak(5) have been measured in 147Sm and 149Sm. Consideration of the k = 2 results together with Woodgate's values of A2(J) for J = 1 to 4 shows that his nonrelativistic treatment of the electric quadrupole interaction in samarium is inadequate but that a relativistic one gives excellent agreement. The effect cannot be confused with a possible configuration interaction as it can in the case of the magnetic dipole interaction. Allowance for the effects of octupolelike second-order corrections and more precise computation of the dipole- and quadrupole-like corrections markedly affect the published results for the hyperfine constants in the lower J states, but the revision does not improve the agreement with the theoretical expressions. It would appear that Conway and Wybourne's analysis of the breakdown of L–S coupling in the nominally 7F ground term is not adequate, particularly for the computation of the coefficient of the sC2 term.

Calculation of the energy-averaged scattering function from high resolution low-energy neutron scattering data

1983 ◽  
Vol 27 (5) ◽  
pp. 1913-1926 ◽  
Author(s):  
C. H. Johnson ◽  
N. M. Larson ◽  
C. Mahaux ◽  
R. R. Winters
Keyword(s):  
High Resolution ◽  
Neutron Scattering ◽  
Low Energy ◽  
Scattering Data ◽  
Scattering Function ◽  
Energy Neutron

Autocorrelation function of the spin misalignment in magnetic small-angle neutron scattering: application to nanocrystalline metals

2013 ◽  
Vol 46 (3) ◽  
pp. 788-790 ◽  
Author(s):  
Andreas Michels ◽  
Jens-Peter Bick
Keyword(s):  
Neutron Scattering ◽  
Autocorrelation Function ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Anisotropy Field ◽  
Real Space ◽  
Scattering Data ◽  
Stiffness Constant ◽  
The Mean ◽  
Cobalt And Nickel

Real-space magnetic small-angle neutron scattering data from nanocrystalline cobalt and nickel have been analysed in terms of a recently developed micromagnetic theory for the autocorrelation function of the spin misalignment [Michels (2010).Phys. Rev. B,82, 024433]. The approach provides information on the exchange-stiffness constant and on the mean magnetic `anisotropy-field' radius.

Characterization of alumina powder using multiple small-angle neutron scattering. I. Theory

1985 ◽  
Vol 18 (6) ◽  
pp. 467-472 ◽  
Author(s):  
N. F. Berk ◽  
K. A. Hardman-Rhyne
Keyword(s):  
Particle Size ◽  
Phase Shift ◽  
Neutron Scattering ◽  
Multiple Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Volume Fraction ◽  
Scattering Data ◽  
Alumina Powder ◽  
Beam Broadening

Microstructural parameters of high-purity alumina powder are determined quantitatively throughout the bulk of the material using small-angle neutron scattering techniques. A unified theoretical and experimental approach for analyzing multiple scattering data is developed to obtain values for particle size, volume fraction and surface area. It is shown how particle size and volume fraction can be measured in a practical way from SANS data totally dominated by incoherent multiple scattering (`beam broadening'). The general phase-shift dependence of single-particle scattering is incorporated into the multiple scattering formalism, and it is also shown that the diffractive limit (small phase shift) applies even for phase shifts as large as unity (particle radii of order 1 μm). The stability of the Porod law against multiple scattering and the phase-shift scale are described, a useful empirical formula for analysis of beam broadening data is exhibited, and the applicability of the formulations to polydispersed systems is discussed.

Structure of Silicon-Substituted Polytricyclononene Films: Small-Angle Neutron Scattering Data

2018 ◽  
Vol 60 (10) ◽  
pp. 2097-2102
Author(s):  
V. T. Lebedev ◽  
N. P. Yevlampieva ◽  
M. V. Bermeshev ◽  
A. A. Szhogina
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Scattering Data

Mössbauer Spectroscopy as a Tool for Materials Research

MRS Bulletin ◽  
1986 ◽  
Vol 11 (6) ◽  
pp. 14-17 ◽  
Author(s):  
John G. Stevens
Keyword(s):  
Hyperfine Interaction ◽  
Isomer Shift ◽  
Quadrupole Splitting ◽  
Electron Density ◽  
Gamma Ray ◽  
Hyperfine Interactions ◽  
Structure Information ◽  
Resolution Capability ◽  
Materials Research ◽  
Mössbauer Parameters

In 1958 Rudolph L. Mössbauer reported his discovery of a simple, practical way of observing nuclear gamma ray resonance. One of the remarkable features of the discovery was the high precision with which energy changes can be measured: energy resolutions of one part to 1011 −1013 are possible. With this high resolution capability it is possible to measure hyperfine interactions between the nucleus of an atom and its electronic environment. These interactions affect the line shape which can be described by several experimental Mössbauer parameters. The three primary parameters are the isomer shift (δ), the quadrupole splitting (Δ), and the magnetic hyperfine interaction.The isomer shift, determined by the position of the centroid of a set of lines in a spectrum, is proportional to the electron density at the nucleus. Since only s electrons have a probability of being at the nucleus, it is possible to obtain electronic structure information such as oxidation state and population of certain molecular orbitals.The quadrupole splitting results when the electron environment surrounding the Mössbauer nucleus is not spherical in its charge distribution. Specifically, Δ is proportional to the imbalance in electron density between the axial and equatorial directions. When this hyperfine interaction is present, there is a quadrupole splitting; i.e., a single spectra line will split into two or more lines.

Theoretical analysis of NMR and neutron scattering data in cerium compounds

1986 ◽  
Vol 33 (7) ◽  
pp. 4522-4525 ◽  
Author(s):  
Nguyen Ngoc Thuan ◽  
L. C. Lopes ◽  
B. Coqblin
Keyword(s):  
Theoretical Analysis ◽  
Neutron Scattering ◽  
Scattering Data ◽  
Cerium Compounds
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