Paramagnetic Defects in Benitoite

1991 ◽  
Vol 46 (7) ◽  
pp. 579-582 ◽  
Author(s):  
A. B. Vassilikou-Dova ◽  
K. Eftaxias
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Hyperfine Interaction ◽  
Relative Intensity ◽  
Room Temperature ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic ◽  
Magnetic Defects

Abstract In clear, blue, transparent bipyramidal crystals of the rare mineral benitoite, BaTiSi3O9, para­ magnetic defects have been investigated by electron paramagnetic resonance at room temperature and 9.43 GHz. They are attributed to Sn3+ and Fe3+ . A pair of satellites recorded for a wide angular rage around B0 || c (~40°) and a relative intensity of ~ 13% to the central signal is most likely due to hyperfine interaction with 117Sn and 119Sn isotopes. Attempts to bleach the colour of the crystal were unsuccessful.

Temperature Dependent Line-Shape of the Silicon Dangling Bond EPR-Resonance in Polycrystalline Silicon

1996 ◽  
Vol 452 ◽  
Author(s):  
N. H. Nickel ◽  
E. A. Schiff
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Polycrystalline Silicon ◽  
Room Temperature ◽  
Dangling Bond ◽  
Temperature Dependent ◽  
Paramagnetic Resonance ◽  
Temperature Electron ◽  
Motional Narrowing ◽  
G Value ◽  
Electron Paramagnetic

AbstractThe temperature dependence of the silicon dangling-bond resonance in polycrystalline (poly-Si) and amorphous silicon (a-Si:H) was measured. At room temperature, electron paramagnetic resonance (EPR) measurements reveal an isotropie g-value of 2.0055 and a line width of 6.5 and 6.1 G for Si dangling-bonds in a-Si:H and poly-Si, respectively. In both materials spin density and g-value are independent of temperature. While in a-Si:H the width of the resonance did not change with temperature, poly-Si exhibits a remarkable T dependence of ΔHpp. In unpassivated poly-Si a pronounced decrease of ΔHpp is observed for temperatures above 300 K. At 384 K ΔHpp reaches a minimum of 5.1 G, then increases to 6.1 G at 460 K, and eventually decreases to 4.6 G at 530 K. In hydrogenated poly-Si ΔHpp decreases monotonically above 425 K. The decrease of ΔHpp is attributed to electron hopping causing motional narrowing. An average hopping distance of 15 and 17.5 Å was estimated for unhydrogenated and H passivated poly-Si, respectively.

Room Temperature Electron Paramagnetic Resonance (EPR) Signal Storage

1969 ◽  
Author(s):  
D.A. Bozanic ◽  
D.C. Buck ◽  
F.H. Harris ◽  
R.E. Huber ◽  
D. Mergerian ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Room Temperature ◽  
Paramagnetic Resonance ◽  
Temperature Electron ◽  
Epr Signal ◽  
Electron Paramagnetic

Transient electron paramagnetic resonance of the triplet state of P700 in photosystem I: Evidence for triplet delocalization at room temperature

Biochemistry ◽  
1993 ◽  
Vol 32 (18) ◽  
pp. 4842-4847 ◽  
Author(s):  
Ina Sieckmann ◽  
Klaus Brettel ◽  
Christian Bock ◽  
Arthur van der Est ◽  
Dietmar Stehlik
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Triplet State ◽  
Photosystem I ◽  
Room Temperature ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

EPR of Gamma-irradiated L-Glutamine Hydrochloride and N-Carbamoyl-L-glutamic Acid

2005 ◽  
Vol 60 (7) ◽  
pp. 549-553 ◽  
Author(s):  
Şemsettin Osmanoğlua ◽  
Murat Aydın ◽  
M. Halim Başkana
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Glutamic Acid ◽  
Radiation Damage ◽  
Single Crystals ◽  
Room Temperature ◽  
Paramagnetic Resonance ◽  
Temperature Radiation ◽  
Gamma Irradiated ◽  
Electron Paramagnetic

The electron paramagnetic resonance spectra of γ -irradiated L-glutamine hydrochloride and N-carbamoyl- L-glutamic acid single crystals have been investigated at room temperature. Radiation damage centres are attributed to ĊH, ṄH2 and CH2Ċ(NH2)COOH radicals.

Hyperfine Interaction of Nitrogen Donor in 4H-SiC Studied by Pulsed-ENDOR

2005 ◽  
Vol 483-485 ◽  
pp. 351-354 ◽  
Author(s):  
Nguyen Tien Son ◽  
Junichi Isoya ◽  
Satoshi Yamasaki ◽  
Erik Janzén
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Hyperfine Interaction ◽  
Spin Density ◽  
Basal Plane ◽  
Double Resonance ◽  
Nearest Neighbour ◽  
Electron Nuclear Double Resonance ◽  
Paramagnetic Resonance ◽  
Nitrogen Donor ◽  
Electron Paramagnetic

Shallow N donors in n-type 4H-SiC were studied by electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR). For the N donor at the cubic site (Nk) in 4H-SiC, the hyperfine (hf) constants of the interaction with the nearest neighbour (NN) 29Si atom along the c axis were determined as A = 41.07 MHz and A^ = 41.31 MHz. For other three NN Si atoms in the basal plane, the hf tensor has C1h symmetry and the principal values Axx = 5.94 MHz, Ayy = 5.06 MHz and Azz = 14.25 MHz. Our EPR and ENDOR observations unambiguously confirm that the N donor occupies the C site in 4H-SiC lattice and also reveal a considerable amount of the spin density of Nk (~23.9%) which was not obtained in previous studies.

Electron Paramagnetic Resonance Study of Ion-Implanted Photorefractive Crystals

1997 ◽  
Vol 504 ◽  
Author(s):  
A. Darwish ◽  
D. Ila ◽  
E. K. Willams ◽  
D. B. Poker ◽  
D. K. Hensley
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Ion Implantation ◽  
Room Temperature ◽  
Electron Paramagnetic Resonance Study ◽  
Paramagnetic Resonance ◽  
Photorefractive Crystals ◽  
Laser Illumination ◽  
Epr Signal ◽  
Electron Paramagnetic

ABSTRACTThe effect of the ion implantation (Fe) on LiNbO3, MgO, and A12O3 crystals is studied using electron paramagnetic resonance (EPR). EPR measurements on these crystals were performed as a function of fluence at room temperature. The fluence was 1 × 1014 and 1 × 1016 ions/cm2. The unpaired carrier concentration increases with increasing fluence. The photosensitivity of these crystals was determined by observing in situ the effect of the laser illumination on the EPR signal and measuring the decay and the growth of the EPR signal. The EPR signal of Fe3+ was found to decrease in both MgO, and Al2O3; and was found to increase in LiNbO3. This indicated that in case of MgO, and A12O3 Fe3+ will transfer into Fe2+/Fe4+, but in case of LiNbO3 Fe2+/ Fe4+ will transfer into Fe3+; increasing the EPR signal. This was found primary due to some Fe2+ and Fe4+ ions, which is not intentionally doped on the LiNbO3 crystal but exist as a defect on the crystal.

Sign in / Sign up

Export Citation Format

Share Document