scholarly journals Electron Spin Resonance Of Vo2+ In Likso4 Single Crystals

2004 ◽  
Vol 59 (7-8) ◽  
pp. 488-490
Author(s):  
Manu Jain
Keyword(s):  
Electron Spin Resonance ◽  
Single Crystals ◽  
Electron Spin ◽  
Esr Spectra ◽  
Spin Hamiltonian ◽  
X Band ◽  
Spin Resonance ◽  
Hamiltonian Parameters

Electron spin resonance of VO2+ doped in LiKSO4 single crystals has been studied at 295 K, using an X-band spectrometer. Three sites have been observed. VO2+ enters the lattice at Li and K substitutional sites. The ESR spectra have been analysed and spin-Hamiltonian parameters evaluated. PACS: 76.30 F

Electron spin resonance of Mn2+ in Cd2V2O7

1968 ◽  
Vol 46 (7) ◽  
pp. 807-810 ◽  
Author(s):  
Carl V. Stager
Keyword(s):  
Electron Spin Resonance ◽  
Single Crystals ◽  
Electron Spin ◽  
Point Charge ◽  
Reasonable Agreement ◽  
Spin Hamiltonian ◽  
Point Charge Model ◽  
Charge Model ◽  
Spin Resonance ◽  
Hamiltonian Parameters

The electron spin resonance of Mn2+ impurities has been investigated in single crystals of Cd2V2O7. The spin-Hamiltonian parameters are gx = 2.0004(8), gy = 1.9995(8), gz = 2.0001(8), b20 = −419(1)g, b22 = 125(2)g, Ax = −86.7(3)g, Ay = −87.0(10)g, and Az = −87.4(5)g. The results have been compared with similar studies on isomorphic crystals and with a calculation employing the point-charge model for the crystal field. The model gives reasonable agreement with the experimental results.

Temperature Dependence of the Crystal-Field Splittings in Gd3+:CaWO4

1971 ◽  
Vol 49 (8) ◽  
pp. 995-1003 ◽  
Author(s):  
J. S. M. Harvey ◽  
H. Kiefte
Keyword(s):  
Electron Spin Resonance ◽  
Low Temperature ◽  
Crystal Field ◽  
Electron Spin ◽  
Fourth Order ◽  
Lattice Vibrations ◽  
Spin Hamiltonian ◽  
Spin Resonance ◽  
Crystal Field Parameters ◽  
Hamiltonian Parameters

The spin-Hamiltonian parameters for Gd3+ in CaWO4 have been measured by the method of electron spin resonance at a number of temperatures between 4.2 °K and 300 °K. The results at 78 °K are in agreement with previous measurements by Hempstead and Bowers.The variations in the crystal-field parameters are interpreted in terms of a limiting low temperature value and a normalized slope at the Debye temperature for each parameter. These quantities are compared with the corresponding quantities for Eu2+ in CaWO4 and, in the case of the fourth-order parameters, for Eu2+ and Gd3+ in cubic CaF2, SrF2, and BaF2. We conclude that the second- and fourth-order splittings each arise from at least three competing mechanisms and that these include a dependence on the amplitude of lattice vibrations. In the case of the trivalent ion, Coulomb forces are also considered to be important.

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.

THE ELECTRON SPIN RESONANCE OF Fe+3 IN SINGLE CRYSTALS OF SPODUMENE

1965 ◽  
Vol 43 (12) ◽  
pp. 2262-2275 ◽  
Author(s):  
A. Manoogian ◽  
F. Holuj ◽  
J. W. Carswell
Keyword(s):  
Electron Spin Resonance ◽  
Single Crystals ◽  
Electron Spin ◽  
Ground State ◽  
Electric Quadrupole ◽  
Spin Hamiltonian ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
Spin Resonance ◽  
Quadrupole Resonance

The electron spin resonance (ESR) spectrum of Fe+3 in spodumene, LiAl(SiO3)2, has been investigated at 24 kMc/sec. One set of five "allowed" transitions between the magnetic sublevels of the 6S5/2 ground state has been detected. The following values have been assigned to the parameters occurring in the spin Hamiltonian (eq. (1)) (bnm in gauss): gx = 2.0086 ± 50, gy = 2.0100 ± 50, gx ± 2.0046 ± 25, b20 = −1 430, b22 = −282, b40 = −20, b42 = 108, b44 = −182. Consideration of electric field gradients measured by methods of electric quadrupole resonance and of the orthorhombic parameters b20 and b22 did not lead to a unique assignment of the Fe+3 impurity to one of the two available cationic sites in spodumene.

ARAGONITE TO CALCITE TRANSFORMATION STUDY BY XRD AND ESR STUDIES OF Mn2+ IN FRESHWATER SNAIL SHELLS: P. CANALICULATA LAMARCK

2006 ◽  
Vol 20 (09) ◽  
pp. 1097-1106 ◽  
Author(s):  
N. UDOMKAN ◽  
P. LIMSUWAN ◽  
Y. CHAIMANEE
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Freshwater Snail ◽  
Esr Spectra ◽  
Resonance Spectroscopy ◽  
Biomineralization Process ◽  
Spin Resonance ◽  
Irreversible Phase Transformation ◽  
Hamiltonian Parameters ◽  
Transformation Study

Electron spin resonance spectroscopy (ESR) was used to study the Mn 2+ ions in snails of P. canaliculata lamarck (PCL). All these shells are abundant in Thailand. Fractions of aragonite and calcite phase in the shells have been approximately determined by ESR. The PCL shell was ground into fine powders and then four samples were separately annealed for 2 h in air at 400°C, 450°C, 500°C and 600°C, respectively. The phase transition from aragonite to calcite was monitored by X-ray diffractometer (XRD) and electron spin resonance spectrometer (ESR). Our results show that unheated PCL sample is mainly made of aragonite with only a small fraction of calcite. Annealing of the PCL powder sample at the temperature more than 450°C has resulted in the irreversible phase transformation from aragonite to calcite. The analysis of their ESR spectra has shown that Mn 2+ ions partially substituted Ca 2+ in the lattices. Finally, the spin Hamiltonian parameters for Mn 2+ distributed in both aragonite and calcite were evaluated. Our detailed ESR spectral analyses of PCL show that Mn 2+ ions enter Ca 2+ sites during a biomineralization process. Typical simulated ESR parameters of PCL-500 of Mn 2+ at a uniaxial site of calcite are gx=gy=2.078(1), gz=1.999(1), Ax=Ay=87.0 G, Az=89.00 G and D=115 G, respectively. It is thus possible to gain some insight of manganese incorporation into the fresh water shells during the biomineralization process.

Structure of radicals produced by γ-radiolysis. Part 4. Adamantane matrices doped with various 5-membered heterocyclic molecules

1976 ◽  
Vol 54 (12) ◽  
pp. 1971-1984 ◽  
Author(s):  
D. L. Winters ◽  
A. Campbell Ling
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Room Temperature ◽  
Esr Spectra ◽  
Heterocyclic Molecules ◽  
First Derivative ◽  
X Band ◽  
Spin Resonance ◽  
Spin Center ◽  
Esr Spectrometry

The effects of γ-adiolysis at room temperature on adamantane and adamantane-d16 matrices doped with 5-membered heterocyclic molecules has been examined by X-band electron spin resonance (esr) spectrometry. Radical structures formed from heterocyclic solute molecules are discussed and tentative assignments made for 2-methyl-, 3-methyl-, and 2,5-dimethylthiophene, 2-methyl-, and 2,5-dimethylfuran. Discussion of possible radical structures derived from furan, tetrahydrofuran, 2-methyl- and 3-methyltetrahydrofuran, 2,5-dihydrofuran, and 4,5-dihydro-2-methylfuran, is included, but unambiguous assignments of structure cannot be made for these compounds from the esr data obtained. Other molecules examined included thiophene, pyrrole, and 1-methyl- and 1,2,5-trimethylpyrrole. For these latter molecules, experimentally obtained first derivative X-band esr spectra were too poorly resolved to allow rational discussion of possible structures. It was noted that perdeuterated adamantane matrices provided superior resolution for esr spectra derived from radicals with a delocalized spin center such as allyl or allenyl species.

High Frequency Electron Spin Resonance Study of Hydrogenated Microcrystalline Silicon

2003 ◽  
Vol 762 ◽  
Author(s):  
Takashi Ehara
Keyword(s):  
Electron Spin Resonance ◽  
Substrate Temperature ◽  
Electron Spin ◽  
Esr Spectra ◽  
Electron Spin Resonance Study ◽  
Dangling Bond ◽  
Microcrystalline Silicon ◽  
W Band ◽  
X Band ◽  
Spin Resonance

AbstractDangling bond defects (DB) in hydrogenated microcrystalline silicon (μc-Si:H) have been studied by X-band (9 GHz) Q-band (33 GHz) and W-band (90 GHz) electron spin resonance (ESR) spectroscopy. In X-band ESR spectra, all the samples showed asymmetric dangling bond defect signal at g = 2.005 – 2.006. The DB signal shape shows little dependence on substrate temperature in the X-band electron spin resonance (ESR) spectra. In the Q-band and W-band ESR spectra, existence of two centers in DB signals is clearly indicated by the shape of the spectra. The Q-band ESR spectra shape reviles that the peak of one center is at g = 2.0055andthe other is around at g = 2.0060. In addition, the DB signal showed dependence on substrate temperature. The dependence of the DB signals can be explained by difference of intensity ratio of the peaks by these two centers. The signal at g = 2.0060 is consistent with the asymmetric ESR signal observed in the microcrystalline silicon embedded in SiO2. W-band ESR measurement indicates that the signal observed at g = 2.0060 is due to single inhomogeneous species and does not consist of plural species.

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