Magnetic resonance, optical and magnetic studies of the nicotinate dihydrates of dysprosium and erbium

1991 ◽  
Vol 434 (1892) ◽  
pp. 695-706 ◽  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Magnetic Resonance ◽  
Ground State ◽  
Zeeman Effect ◽  
Dipole Interaction ◽  
Nearest Neighbour ◽  
Magnetic Studies ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic ◽  
Made In

Measurements have been made in lanthanide nicotinate dihydrate (LnND) single crystals, where Ln ═ Dy and Er, of optical absorption, including the Zeeman effect, of magnetic susceptibility between 1.4 and 4.2 K, of electron paramagnetic resonance between about 9 and 35 GHz, and of magnetic resonance at 22 MHz. As in the case of TmND (Baker et al . 1986 a ), the measurements are consistent with a ground state with a large amplitude of M j ═ ± J , an almost Ising-like g -matrix, and a purely magnetic dipole-dipole interaction between nearest-neighbour Ln 3+ ions. In this respect, the Kramers ions Dy 3+ and Er 3+ exhibit features similar to the non-Kramers ions Tb 3+ and Tm 3+ in the nicotinate dihydrates.

Electron paramagnetic resonance, optical and magnetic studies of Tb 3+ in lanthanide nicotinate dihydrates

1987 ◽  
Vol 413 (1845) ◽  
pp. 515-528 ◽  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Optical Absorption ◽  
Ground State ◽  
Zeeman Effect ◽  
Optical Absorption Spectroscopy ◽  
Site Symmetry ◽  
Magnetic Studies ◽  
Paramagnetic Resonance ◽  
Defect Sites ◽  
Electron Paramagnetic

Optical absorption and fluorescence, magnetic susceptibility and electron magnetic resonance experiments have been made of Tb 3+ , 4f 8 , ions in lanthanide nicotinate dihydrate single crystals. Optical absorption spectroscopy in undiluted terbium nicotinate dihydrate (TbND) indicates that the ground state of Tb 3+ , 7 F 6 , is a singlet exhibiting a quadratic Zeeman effect, and this is confirmed by the observation of a temperature-independent Van Vleck paramagnetism below 4.2 K. This is what one would expect for a non-Kramers ion in a crystal field of no symmetry. In spite of this, electron paramagnetic resonance (epr) is observed from Tb 3+ ions both in dilute LaND containing 0.01 mole fraction of Tb and in TbND. In the dilute material, in spite of the absence of site symmetry, the results show a nearly degenerate non-Kramers doublet with a g value of 17.2(8), close to the maximum possible value of 12 g j ; the ground state must therefore be predominantly M j = ±6. The epr in TbND arises from some type of defect site involving two interacting dissimilar Tb 3+ ions. The spectrum of Tb 3+ ions observed by optical fluorescence is also attributed to defect sites.

Magnetic resonance studies of Dy 3+ and Er 3+ in lanthanum nicotinate dihydrate

1991 ◽  
Vol 434 (1892) ◽  
pp. 707-717 ◽  
Keyword(s):  
Single Crystals ◽  
Magnetic Dipole ◽  
Ground State ◽  
Principal Direction ◽  
Dipole Interaction ◽  
Nearest Neighbour ◽  
Paramagnetic Resonance ◽  
Magnetic Resonance Studies ◽  
Principal Value ◽  
Electron Paramagnetic

Electron paramagnetic resonance (EPR) measurements have been made on Dy 3+ and Er 3+ in lanthanum nicotinate dihydrate (LaND) single crystals, for comparison with the information described in the previous paper about single crystals of DyND and ErND. For both DyND and ErND, as for TmND, the measurements were found to be consistent with a ground state with a large amplitude of M j ═ ± J , an almost Ising-like g -matrix, and a purely magnetic dipole-dipole interaction between nearest neighbour (NN) Ln 3+ ions, where Ln is either Dy or Er. In contrast, for Ln 3+ dilutely substituted into LaND, although the g -matrix has one principal value much larger than the other two, the principal direction is different from that for LnND. EPR in crystals of LaND containing between 0.01 and 0.1 mole fraction of Ln shows that isolated ions have a g -matrix very similar to that in more dilute crystals, and NN pairs have a g -matrix similar to that for LnND and a purely magnetic dipole-dipole interaction. Hence, the Kramers ions Dy 3+ and Er 3+ are seen to exhibit the same features as were found for the non-Kramers ions Tb 3+ and Tm 3+ in the lanthanide nicotinate dihydrates.

Interaction of Point Defects with Impurities in the Si-SiO2 System and its Influence on the Properties of the Interface

2009 ◽  
Vol 156-158 ◽  
pp. 145-148 ◽  
Author(s):  
Daniel Kropman ◽  
E. Mellikov ◽  
K. Lott ◽  
Tiit Kärner ◽  
Ivo Heinmaa ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Magnetic Resonance ◽  
Fermi Level ◽  
Point Defects ◽  
Interface Properties ◽  
Hydrogen Ions ◽  
Paramagnetic Resonance ◽  
Proposed Model ◽  
P Type ◽  
Electron Paramagnetic

The results of investigation of the point defect generation and interaction with impurities in the Si-SiO2 system during the process of its formation by means of electron paramagnetic resonance (EPR) and nucleous magnetic resonance (NMR) technique are presented. It has been shown that the diference in point defects interaction with hydrogen at the Si-SO2 interface with n- and p-type conductivity are connected with the sign of hydrogen ions incorporation dependence on the Fermi level position in accordance with the proposed model. The interface properties may be improved by laser irradiation.

Sign in / Sign up

Export Citation Format

Share Document