Electron spin resonance of Mn2+ impurities in morinite

1969 ◽  
Vol 47 (17) ◽  
pp. 1869-1875 ◽  
Author(s):  
A. Manoogian ◽  
Y. Hsu
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Room Temperature ◽  
Microwave Frequency ◽  
Heat Treating ◽  
Orthorhombic Symmetry ◽  
Spin Hamiltonian ◽  
Frequency Range ◽  
Spin Resonance ◽  
Impurity Ions

The electron spin resonance of Mn2+ impurity ions in natural crystals of morinite, Ca4Na2Al4(F, OH)10(PO4)4∙3H2O, was studied in the 9.4 GHz microwave frequency range and at room temperature. A single magnetic complex was found and the resonance lines were characterized by strong splittings due to superhyperfine interactions with ligand nuclei. The resonance lines were fitted to a spin Hamiltonian of orthorhombic symmetry and the following parameters were determined: gz = 2.0014 ± 0.0005, gy = 2.0017 ± 0.0010, b2°= 166.8 ± 1.5, b22 = 69.1 ± 1.5, b40 = −0.17 ± 0.10, A = 98.2 ± 1.0, and B = C = 99.7 ± 1.5. The values of bnm, A, B, and C are in gauss, and the signs are relative. By heat-treating powdered samples of morinite to a temperature greater than 400 °C, it was shown that the morinite changed to apatite, 2[Ca5(PO4)3(F, OH)].

The electron spin resonance of Mn2+ in tremolite

1968 ◽  
Vol 46 (2) ◽  
pp. 129-133 ◽  
Author(s):  
A. Manoogian
Keyword(s):  
Electron Spin Resonance ◽  
Angular Dependence ◽  
Electron Spin ◽  
Room Temperature ◽  
Microwave Frequency ◽  
Orthorhombic Symmetry ◽  
Spin Hamiltonian ◽  
Frequency Range ◽  
Line Intensities ◽  
Spin Resonance

The electron spin resonance of Mn2+ ion impurities in natural crystals of tremolite, 2(H2Ca2Mg5-(SiO3)8), was studied in the 9.2 GHz microwave frequency range, and at room temperature. The work was done on two crystals of tremolite containing different concentrations of Mn2+. In each case only one magnetic complex of Mn2+ was found. The resonance lines are characterized by a strong angular dependence of the line intensities, and this is coupled with the appearance of many forbidden lines of Mn2+. The resonance lines of the allowed transitions were fitted to a spin Hamiltonian of orthorhombic symmetry.

ELECTRON SPIN RESONANCE OF Fe+3 IN CORDIERITE

1966 ◽  
Vol 44 (11) ◽  
pp. 2749-2755 ◽  
Author(s):  
N. E. Hedgecock ◽  
S. C. Chakravartty
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Room Temperature ◽  
Esr Spectra ◽  
Orthorhombic Symmetry ◽  
Zero Field ◽  
Spin Hamiltonian ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Spin Resonance

ESR spectra of Fe+3 located at one of the aluminium sites in cordierite have been investigated at X- and K-band frequencies at room temperature. The spectra exhibit large zero-field splitting and have been fitted to a spin Hamiltonian of orthorhombic symmetry, having constants b20 = 14.6 ± 0.1 kG, b22 = 8.5 ± 0.1 kG, and isotropic g = 2.004 ± 0.002.

THE ELECTRON SPIN RESONANCE OF VO2+ IONS IN TWO TYPES OF ALUMINIUM ALUMS

1967 ◽  
Vol 45 (8) ◽  
pp. 2769-2777 ◽  
Author(s):  
A. Manoogian ◽  
J. A. MacKinnon
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Room Temperature ◽  
Resonance Spectrum ◽  
Microwave Frequency ◽  
Spin Hamiltonian ◽  
Vanadyl Ion ◽  
Spin Resonance ◽  
Hamiltonian Parameters ◽  
Crystallographic Axes

The electron spin resonance spectrum of the vanadyl ion VO2+ is studied in single crystals of RbAl(SO4)2.12 H2O and CsAl(SO4)2.12 H2O, at room temperature and in the 9.2 kMc/s microwave frequency range. In RbAl(SO4)2.12 H2O the V–O axes are found to have three orientations directed along the cubic crystallographic axes, giving rise to three magnetic complexes. The spin Hamiltonian parameters are S = 1/2, [Formula: see text], [Formula: see text], [Formula: see text] cm−1, and [Formula: see text] cm−1. In CsAl(SO4)2.12 H2O the V–O axes are displaced from the crystallographic axes, giving rise to 12 magnetic complexes. The spin Hamiltonian parameters are S = 1/2, [Formula: see text], [Formula: see text], [Formula: see text] cm−1, and [Formula: see text] cm−1. The observed spectra are attributed to a vanadyl pentahydrate complex (VO2+.5 H2O) associated with a water-molecule vacancy.

scholarly journals Ferromagnetic Resonance Characterization of Nano-FePt by Electron Spin Resonance

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
S. S. Nkosi ◽  
H. M. Gavi ◽  
D. E. Motaung ◽  
J. Keartland ◽  
E. Sideras-Haddad ◽  
...  
Keyword(s):  
Electron Spin Resonance ◽  
Data Storage ◽  
Ferromagnetic Resonance ◽  
Electron Spin ◽  
Iron Content ◽  
Room Temperature ◽  
Large Data ◽  
Microwave Frequency ◽  
Homogeneous Distribution ◽  
Spin Resonance

Electron spin resonance (ESR) measurements at room temperature and X-band microwave frequency were performed on highly crystalline FePt system thin films. Fairly high DC static magnetic field absorption of about 300 mT was observed in these films. We attribute the high field absorption to ferromagnetic resonance (FMR). Upon increasing iron content in FePt system, no detectable spin waves modes were identified already at room temperature. This signifies a homogeneous distribution of the magnetization across the films. We qualitatively attributed such homogeneity distribution in the films to self-assembly of these Fe–Pt system nanoparticles. The results revealed that the FePt system contains hyperfine coupling with sextetI=5/2exhibiting a phase reversal behaviour compared to FMR line. Both iron content and crystallite size increased the FMR intensity making the films good candidates for large data storage mediums and spintronics.

AN ELECTRON SPIN RESONANCE STUDY OF MANGANESE IMPURITY IN BRUCITE

1961 ◽  
Vol 39 (1) ◽  
pp. 145-157 ◽  
Author(s):  
W. A. Pieczonka ◽  
H. E. Petch ◽  
A. B. McLay
Keyword(s):  
Absorption Spectrum ◽  
Electron Spin Resonance ◽  
Single Crystal ◽  
Electron Spin ◽  
Room Temperature ◽  
Electron Spin Resonance Study ◽  
Spin Hamiltonian ◽  
Air Temperatures ◽  
Spin Resonance ◽  
Spin Resonance Study

A single crystal of brucite, Mg(OH)2, containing manganese impurity to the extent of 100 parts per million, has been studied by means of the electron spin resonance (esr) technique. The study was made at room and liquid air temperatures. The observed absorption spectrum has been successfully interpreted in terms of parameters found in the appropriate spin-Hamiltonian. The measured values of these parameters at room temperature were found to be:[Formula: see text]

Electron spin resonance of Mn2+ impurities in monticellite

1969 ◽  
Vol 47 (8) ◽  
pp. 839-846 ◽  
Author(s):  
A. G. Danilov ◽  
A. Manoogian
Keyword(s):  
Electron Spin Resonance ◽  
Electric Fields ◽  
Electron Spin ◽  
Microwave Frequency ◽  
Spectral Lines ◽  
Orthorhombic Symmetry ◽  
Principal Axes ◽  
Spin Resonance ◽  
Crystalline Electric Fields ◽  
Crystallographic Axes

The electron spin resonance of Mn2+ impurity ions in natural crystals of monticellite, MgCaSiO4, was studied in the 9.4 GHz and 35 GHz microwave frequency ranges, and at room temperature. Four magnetic complexes of manganese were observed, and these were found to degenerate into two in the (010) crystallographic plane. The magnetic field separations of the spectral lines along the principal axes of the crystalline electric fields were the same for all four complexes. The resonance lines were fitted to a spin Hamiltonian of orthorhombic symmetry, and the following parameters were determined: gz = 1.9961, gy = 1.9905, b20 = −558.5, b22 = −351.7, b40 = −0.5, b42 = −56.0, b44 = −40.3, A = 85.5, B = 85.5. The values of bnm, A, and B are in gauss, and the signs are relative. It was possible to relate the axes of the Mn2+ magnetic complexes to the crystallographic axes. Hence, it was determined that the Mn2+ ions replace Mg2+ ions, which are in centers with inversion symmetry, and not Ca2+ ions, which are in centers containing a reflection plane.

Intensity of allowed and forbidden electron spin resonance lines of Mn2+ in tremolite

1968 ◽  
Vol 46 (9) ◽  
pp. 1029-1033 ◽  
Author(s):  
A. Manoogian
Keyword(s):  
Electron Spin Resonance ◽  
Electric Fields ◽  
Electron Spin ◽  
Theoretical Calculations ◽  
Microwave Frequency ◽  
Orthorhombic Symmetry ◽  
Crystalline Electric Field ◽  
Line Intensities ◽  
Spin Resonance ◽  
Crystalline Electric Fields

The angular variation of the intensities of the allowed and forbidden (Δm = ±1) electron spin resonance lines of Mn2+ impurities in tremolite, 2(H2Ca2Mg5(SiO3)8), was studied at room temperature and in the 9.2-GHz microwave frequency range. The crystalline electric field for the magnetic complex of Mn2+ in tremolite has orthorhombic symmetry, and this causes the line intensities to vary asymmetrically between the z and y magnetic axes. The experimental measurement of these intensities is in good agreement with the theoretical calculations of Bir (1964). Bir's theory has been used with success previously by others for ions in the higher-symmetry axial and cubic crystalline electric fields.

scholarly journals Force detection of high-frequency electron spin resonance near room temperature using high-power millimeter-wave source gyrotron

2021 ◽  
Vol 118 (2) ◽  
pp. 022407
Author(s):  
Hideyuki Takahashi ◽  
Yuya Ishikawa ◽  
Tsubasa Okamoto ◽  
Daiki Hachiya ◽  
Kazuki Dono ◽  
...  
Keyword(s):  
Electron Spin Resonance ◽  
Millimeter Wave ◽  
Electron Spin ◽  
High Power ◽  
High Frequency ◽  
Room Temperature ◽  
Force Detection ◽  
Wave Source ◽  
Spin Resonance ◽  
Millimeter Wave Source

Radiation damage in polyethylene as studied by electron spin resonance

1961 ◽  
Vol 262 (1309) ◽  
pp. 207-218 ◽  
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Alkyl Radical ◽  
Room Temperature ◽  
Chemical Properties ◽  
Resonance Method ◽  
Alkyl Radicals ◽  
Spin Resonance ◽  
Physical And Chemical ◽  
Kinetics Of

The electron spin resonance method was employed to study the nature, concentration and kinetics of the disappearance under varying conditions of radicals produced in polyethylene by fast electron irradiation at 77°K. The predominant radical species at 77°K is the alkyl radical —CH 2 —ĊH—CH 2 —. On being warmed to room temperature it disappears rapidly, revealing a more stable un­identified radical. The kinetics of the decay at room temperature of both radicals was observed. Their stabilities were found to vary in polyethylene samples of differing physical and chemical properties. G values for these radicals are given. Comparison was made with spectra obtained under similar conditions with two pure paraffins and a pure olefin to evaluate the effect of crystallinity branching, molecular weight and unsaturation. In the olefin there is evidence for a build-up of allyl radicals due to the encounter of an alkyl radical with main chain unsaturation. This supports the view that alkyl radicals are mobile, and cross-linking occurs when two such radicals meet.

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