A fast "τx" spin–lattice relaxation process in phosphorus donor pairs in silicon

1970 ◽  
Vol 48 (7) ◽  
pp. 834-841 ◽  
Author(s):  
J. R. Marko
Keyword(s):  
Lattice Relaxation ◽  
Exchange Energy ◽  
Spin Lattice Relaxation ◽  
Single Atom ◽  
Relaxation Processes ◽  
Lattice Vibrations ◽  
Linear Combinations ◽  
Spin Lattice ◽  
Electronic Spin ◽  
Pair Exchange

A mechanism is proposed to explain the observed fast τx spin–lattice relaxation processes observed in close phosphorus donor pairs in silicon. The mechanism is based on a mixing of states of different total electronic spin by the hyperfine interaction and a modulation of the pair exchange energy by the lattice vibrations. The exchange-energy expression used is calculated from single-atom wave functions composed of linear combinations of the Bloch states at the six conduction-band minima. The resultant relaxation rate is shown to agree with experimental observations.

Calculation of NQR v's and T1-1' s being proportional to T4 and T5 , respectively

1990 ◽  
Vol 45 (3-4) ◽  
pp. 536-540
Author(s):  
Mariusz Máckowiak ◽  
Costas Dimitropoulos
Keyword(s):  
Temperature Dependence ◽  
Relaxation Rate ◽  
Spin System ◽  
Low Frequency ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Lattice Vibrations ◽  
Spin Lattice ◽  
Simplifying Assumptions ◽  
The One

Abstract The second-order Raman phonon process for a multilevel spin system is shown to give a quadru-polar spin-lattice relaxation rate T1-1varying as T5 at very low temperatures. This relaxation rate for quadrupole spins is similar to the one discussed for a paramagnetic spin system having a multilevel ground state. The temperature dependence of T1 is discussed on the basis of some simplifying assumptions about the nature of the lattice vibrations in the Debye approximation. This type of relaxation process has been observed below 20 K in tetramethylammonium hydrogen bis-trichloroacetate for the 35Cl T1-1 . Below 20 K the NQR frequency in the same crystal reveals a T4 temperature dependence due to the induced modulations of the vibrational and librational coordinates by the low-frequency acoustic phonons.

A Study of Spin-Phonon Interactions by Spin-Lattice Relaxation Processes

1976 ◽  
pp. 214-216
Author(s):  
C. A. Bates ◽  
A. Gavaix ◽  
P. Steggles ◽  
H. Szymczak ◽  
A. Vasson ◽  
...  
Keyword(s):  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Relaxation Processes ◽  
Spin Lattice

Spin-lattice relaxation processes of transition metal ions in a heavily cobalt doped ZnO: Phonon heating effect

2019 ◽  
Vol 126 (12) ◽  
pp. 123903
Author(s):  
D. V. Azamat ◽  
A. G. Badalyan ◽  
P. G. Baranov ◽  
M. Fanciulli ◽  
J. Lanc̆ok ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Lattice Relaxation ◽  
Transition Metal Ions ◽  
Spin Lattice Relaxation ◽  
Relaxation Processes ◽  
Heating Effect ◽  
Spin Lattice ◽  
Doped Zno

Spin-Gitter-Relaxation im Triplett-Zustand von Chinoxalin in Perdeutero-Naphthalin und zwei ähnlichen Mischkristallen

1975 ◽  
Vol 30 (6-7) ◽  
pp. 754-770 ◽  
Author(s):  
U. Konzelmann ◽  
D. Kilpper ◽  
M. Schwoerer
Keyword(s):  
Triplet State ◽  
Deep Trap ◽  
Lattice Relaxation ◽  
Relaxation Mechanism ◽  
Mixed Crystals ◽  
Spin Lattice Relaxation ◽  
Relaxation Processes ◽  
Shallow Trap ◽  
Field Range ◽  
Spin Lattice

Abstract Spin Lattice Relaxation in the Triplet State of Qainoxaline in Perdeuteronaphthalene and of two Similar Mixed Crystals The spin lattice relaxation in the excited triplet state of three mixed crystals was investigated: Quinoxaline in perdeutero-naphthalene, quinoxaline in naphthalene (X-traps) and quinoxaline in durene. They differ by the depth of their traps, which are shallow (90 cm -1), very shallow (60 cm -1) and deep (6600 cm -1), respectively. In order to identify the relaxation processes and the relaxation mechanism, the experiments were performed in the large magnetic field range be-tween 0.2 T and 5.4 T. By use of a non-resonant optical method and by ESR and ODMR it could be shown that at high fields the direct process (emission of resonant phonons) is the only efficient process up to 4.2 K. At low fields Raman-processes are dominant. Thereby the spin lattice relaxation probability per unit time, w, increases with the ninth power of the temperature in the shallow trap systems and with the fifth power in the deep trap system. By the analysis of the very strong anisotropy of w it could be shown that the efficient relaxation mechanism in the shallow trap systems is a guest-host-interaction modulated by phonons.

35Cl NQR Studies of Bismuth Trichloride

1997 ◽  
Vol 52 (8-9) ◽  
pp. 614-620
Author(s):  
P. K. Babu ◽  
J. Ramakrishna
Keyword(s):  
Temperature Dependence ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Positive Temperature Coefficient ◽  
Spin Lattice Relaxation ◽  
Positive Temperature ◽  
Lattice Vibrations ◽  
Spin Lattice ◽  
Quadrupole Resonance ◽  
35Cl Nqr

Abstract The temperature dependence of the 35Cl nuclear quadrupole resonance (NQR) frequency and spin lattice relaxation time (T1) are studied in crystalline BiCl3 , in the range 40-300 K. The positive temperature coefficient observed for one of the 35Cl resonances is explained in terms of the strong intermolecular interactions that exist in this compound. Variation of with temperature is found to be similar at the chemically inequivalent halogen sites. Semiclassical descriptions based on torsional oscillator dynamics are found to be inadequate for explaining the spin lattice relaxation. T1 (T) data follow an AT2 + BT3 type behaviour, indicating that the anharmonic nature of the lattice vibrations plays a significant role in determining the temperature dependence of T1 at high temperatures.

Molecular dynamics of poly(ethylene terephthalate)/poly(phenylene sulfide) nanocomposites with barium titanate

Open Physics ◽  
2011 ◽  
Vol 9 (2) ◽  
Author(s):  
Monika Konieczna ◽  
Aneta Woźniak-Braszak ◽  
Krystyna Hołderna-Natkaniec ◽  
Jan Jurga
Keyword(s):  
Barium Titanate ◽  
Ethylene Terephthalate ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Relaxation Processes ◽  
Spin Lattice ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene ◽  
Phenylene Sulfide

AbstractThe relaxation processes and the properties of polymer/ceramic nanocomposites have been studied by the 1H nuclear magnetic resonance methods. Nanocomposites of poly(ethylene terephthalate) PET and poly(phenylene sulfide) PPS with 0.25, 2.5 and 5% wt. barium titanate BT were prepared using a twin screw extruder and injection moulding machine. The spin-lattice relaxation time T1, second moment M2 and the motional parameters as e.g. the activation energies in the nanocomposites were investigated.

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