A Novel Electron Paramagnetic Resonance Phenomenon in a Barium Stronium Titanate Ceramic

2011 ◽  
Vol 295-297 ◽  
pp. 1050-1054 ◽  
Author(s):  
Da Yong Lu ◽  
Xiu Yun Sun
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Resonance Phenomenon ◽  
Tetragonal Symmetry ◽  
Paramagnetic Resonance ◽  
Vacancy Defects ◽  
Average Size ◽  
Increasing Temperature ◽  
Titanate Ceramics ◽  
Electron Paramagnetic ◽  
Titanate Ceramic

The electron paramagnetic resonance (EPR) technique was employed to investigate the point defects in barium strontium titanate ceramics. All samples showed a strong EPR signal with g = 2.000, which was indexed as intrinsic Ti-vacancy defects. In (Ba0.85Sr0.15)TiO3ceramic, which showed a tetragonal symmetry and consisted of the crystallites with average size of ~ 220 nm, a novel EPR powder spectrum was observed - the g-factor of theg= 2.000 signal evolved into ag-tensor, and the two weak signals withg3= ~ 2.6 andg1= ~ 1.6 gradually shifted toward the g2 = 2.000 signal and approached to each other with increasing temperature.

Investigations of the EPR g Factors for Er3+ in CaMoO4

2004 ◽  
Vol 59 (6) ◽  
pp. 341-345 ◽  
Author(s):  
Shao-Yi Wu ◽  
Hui-Ning Dong
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Crystal Field ◽  
Structural Data ◽  
Order Perturbation ◽  
Tetragonal Symmetry ◽  
Superposition Model ◽  
Paramagnetic Resonance ◽  
Crystal Field Parameters ◽  
Electron Paramagnetic ◽  
G Factors

The electron paramagnetic resonance (EPR) g factors g‖ and g⊥ for Er3+ in CaMoO4 are theoretically investigated by using the perturbation formulas of the g factors for a 4f11 ion in tetragonal symmetry. In these formulas, the contributions to the g factors arising from the second-order perturbation terms and the admixture of various states are considered. The crystal-field parameters for the tetragonally distorted tetrahedra are determined by using the superposition model and the structural data of the impurity Er3+ on the host Ca2+ site in CaMoO4. The calculated g factors agree with the observed values. The validity of the results is discussed.

scholarly journals Singlet oxygen generation by higher fullerene-based colloids

2010 ◽  
Vol 75 (7) ◽  
pp. 965-973 ◽  
Author(s):  
Svetlana Jovanovic ◽  
Zoran Markovic ◽  
Duska Kleut ◽  
Vladimir Trajkovic ◽  
Branka Babic-Stojic ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Singlet Oxygen ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Paramagnetic Resonance ◽  
Oxygen Generation ◽  
Force Microscopy ◽  
Water Based ◽  
Average Size ◽  
Electron Paramagnetic

In this paper, the results of the synthesis and characterization of higher fullerene-based colloids is presented. The generation of singlet oxygen 1O2 (1?g) by fullerene water-based colloids (nC60, nC70 and nC84) was investigated. It was found by electron paramagnetic resonance spectroscopy that the generation of singlet oxygen was the highest by the nC84 colloid. The amplitude of the electron paramagnetic resonance (EPR) signal was two orders of magnitude higher than the amplitude of the EPR signals which originated from nC60 and nC70. The surface morphology and the structure of the particles of the water-based colloids were investigated by atomic force microscopy (AFM). The AFM study showed that the average size of the nC60, nC70 and nC84 were 200 nm, 80 nm and 70 nm, respectively. In addition, the particle size distribution of the nC60, nC70 and nC84 colloids was determined by dynamic light scattering (DLS) measurements.

Electron paramagnetic resonance study of hydrogen-vacancy defects in crystalline silicon

1998 ◽  
Vol 58 (7) ◽  
pp. 3842-3852 ◽  
Author(s):  
P. Stallinga ◽  
P. Johannesen ◽  
S. Herstrøm ◽  
K. Bonde Nielsen ◽  
B. Bech Nielsen ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Crystalline Silicon ◽  
Electron Paramagnetic Resonance Study ◽  
Paramagnetic Resonance ◽  
Vacancy Defects ◽  
Hydrogen Vacancy ◽  
Electron Paramagnetic

Theoretical Studies of the EPR Parameters of Nd3+ in LiYF4

2004 ◽  
Vol 59 (4-5) ◽  
pp. 235-238 ◽  
Author(s):  
Shao-Yi Wu ◽  
Hui-Ning Dong
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Crystal Field ◽  
Structural Parameters ◽  
Tetragonal Symmetry ◽  
Theoretical Studies ◽  
Superposition Model ◽  
Paramagnetic Resonance ◽  
Epr Parameters ◽  
Crystal Field Parameters ◽  
Electron Paramagnetic

The perturbation formulas of the electron paramagnetic resonance (EPR) parameters g∥, g⊥, A∥ and A⊥ for a 4f3(Nd3+) ion in tetragonal symmetry are established in this work. In these formulas, the contributions to the EPR parameters arising from the second-order perturbation terms and the admixtures of different states are included. Then the above formulas are applied to a tetragonal Nd3+ center in LiYF4, where the related crystal-field parameters are calculated from the superposition model and the local structural parameters of the Y3+ site occupied by the impurity Nd3+. The EPR parameters and the optical spectra within the 4I9/2 and 4I11/2 states obtained in this work agree reasonably with the observed values.

Sign in / Sign up

Export Citation Format

Share Document