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.

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.

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 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.

Electron spin resonance study of SO2 and CO on CuO–alumina

1982 ◽  
Vol 60 (18) ◽  
pp. 2340-2341 ◽  
Author(s):  
K. C. Khulbe ◽  
R. S. Mann
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Room Temperature ◽  
Electron Spin Resonance Study ◽  
Alumina Catalyst ◽  
Treated Sample ◽  
Spin Resonance ◽  
Spin Resonance Study

The intensity of the Cu2+ esr signal increased significantly on the addition of CO or SO2, especially with SO2, at room temperature to the preheated (at 400 °C) and evacuated CuO–alumina catalyst. When the CO or SO2 treated sample was evacuated at room temperature, the shape and intensity of the Cu2+ esr line returned to their original values. The intensity of the Cu2+ esr line decreased, but not to zero, on heating CuO–alumina either with CO or SO2. In the case of SO2, a new line appeared for the [Formula: see text] ion which was not affected on evacuation. It seems that the [Formula: see text] do not take part in the reduction of SO2 with CO over the CuO–alumina catalyst.

Sign in / Sign up

Export Citation Format

Share Document