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.

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.

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 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)].

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.

Anomalous absorption of Cr3+ electron spin resonance line intensities in guanidinium aluminum sulfate hexahydrate crystals

1981 ◽  
Vol 59 (8) ◽  
pp. 1020-1024 ◽  
Author(s):  
A. Manoogian
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Resonance Line ◽  
Aluminum Sulfate ◽  
Electron Spin Resonance Line ◽  
Anomalous Absorption ◽  
Line Intensities ◽  
Spin Resonance ◽  
Impurity Ions ◽  
Frequency Power

Experimental results are presented describing an anomalous absorption observed as a function of temperature for Cr3+ impurity ions in guanidinium aluminum sulfate hexahydrate (GAlSH) crystals. Measurements were made of the Cr3+ electron spin resonance line intensities, and a plot of the results upon cooling and warming the crystal shows the presence of an anomaly centered at a temperature of 280 K. The same effect was observed in measurements of the capacitance of undoped GAlSH crystals. The anomaly was found to be enhanced by the application of radio frequency power at 200 MHz to the crystal.

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