Nuclear Polarization and Impurity-State Spin Relaxation Processes in Silicon

1957 ◽  
Vol 106 (3) ◽  
pp. 489-498 ◽  
Author(s):  
David Pines ◽  
John Bardeen ◽  
Charles P. Slichter
Keyword(s):  
Spin Relaxation ◽  
Nuclear Polarization ◽  
Impurity State ◽  
Relaxation Processes ◽  
State Spin

Proton Spin Relaxation of a Liquid Crystal with a Glassy Cholesteric State

1990 ◽  
Vol 45 (9-10) ◽  
pp. 1077-1084 ◽  
Author(s):  
D. Pusiol ◽  
F. Noack ◽  
C. Aguilera
Keyword(s):  
Spin Relaxation ◽  
Rotational Diffusion ◽  
Glassy State ◽  
Larmor Frequency ◽  
Proton Spin ◽  
Relaxation Dispersion ◽  
Proton Relaxation ◽  
Relaxation Processes ◽  
Molecular Reorientation ◽  
Cholesteric Phase

Abstract Field-cycling and standard pulsed NMR techniques have been used to study the frequency dependence of the longitudinal proton spin relaxation time T x in the crystalline estradiol compound (+)3,1,7-ß-bis-(4n-butoxybenzoyloxy)-estra-1,3,5-(10)-trien or BET, which is a mesogenic material with a chiral molecular structure. From the measured Larmor frequency and temperature depen-dences we conclude that, at low NMR frequencies in the cholesteric phase, T1 reflects in addition to the relaxation process familiar from nematic liquid crystals (director fluctuation modes) another slow mechanism theoretically predicted for cholesteric systems, namely diffusion induced rotational molecular reorientation. These relaxation processes are not or much less effective in the crystalline and glassy state, where they are frozen. Also the high NMR frequency relaxation dispersion strongly differs between the cholesteric mesophase and the not liquid crystalline samples. This is interpreted by a change from essentially translational self-diffusion to rotational diffusion controlled proton relaxation.

scholarly journals Evolution of spin relaxation processes in LiY1−xHoxF4studied via ac-susceptibility and muon spin relaxation

2012 ◽  
Vol 86 (1) ◽  
Author(s):  
R. C. Johnson ◽  
B. Z. Malkin ◽  
J. S. Lord ◽  
S. R. Giblin ◽  
A. Amato ◽  
...  
Keyword(s):  
Spin Relaxation ◽  
Muon Spin ◽  
Ac Susceptibility ◽  
Muon Spin Relaxation ◽  
Relaxation Processes

scholarly journals Maximizing NMR signal per unit time by facilitating the e–e–n cross effect DNP rate

2018 ◽  
Vol 20 (43) ◽  
pp. 27646-27657 ◽  
Author(s):  
Alisa Leavesley ◽  
Sheetal Jain ◽  
Ilia Kamniker ◽  
Hui Zhang ◽  
Suchada Rajca ◽  
...  
Keyword(s):  
Spin Relaxation ◽  
Electron Spin ◽  
Dynamic Nuclear Polarization ◽  
Nuclear Spin ◽  
Nuclear Polarization ◽  
Nuclear Spin Relaxation ◽  
Cross Effect ◽  
Spin Clusters

Dynamic nuclear polarization (DNP) efficiency is critically dependent on the properties of the radical, solvent, and solute, where electron spin clusters will shorten nuclear spin relaxation and enhance CE-DNP.

scholarly journals Dipolar spin relaxation of divacancy qubits in silicon carbide

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Oscar Bulancea-Lindvall ◽  
Nguyen T. Son ◽  
Igor A. Abrikosov ◽  
Viktor Ivády
Keyword(s):  
Magnetic Field ◽  
Silicon Carbide ◽  
Relaxation Time ◽  
Spin Relaxation ◽  
Theoretical Study ◽  
Coherence Time ◽  
The Other ◽  
Relaxation Processes ◽  
Nuclear Spins ◽  
Open Questions

AbstractDivacancy spins implement qubits with outstanding characteristics and capabilities in an industrial semiconductor host. On the other hand, there are still numerous open questions about the physics of these important defects, for instance, spin relaxation has not been thoroughly studied yet. Here, we carry out a theoretical study on environmental spin-induced spin relaxation processes of divacancy qubits in the 4H polytype of silicon carbide (4H-SiC). We reveal all the relevant magnetic field values where the longitudinal spin relaxation time T1 drops resonantly due to the coupling to either nuclear spins or electron spins. We quantitatively analyze the dependence of the T1 time on the concentration of point defect spins and the applied magnetic field and provide an analytical expression. We demonstrate that dipolar spin relaxation plays a significant role both in as-grown and ion-implanted samples and it often limits the coherence time of divacancy qubits in 4H-SiC.

The duality of electron spin and resistivity relaxation processes in sodium and potassium metals

1984 ◽  
Vol 395 (1809) ◽  
pp. 341-351 ◽  
Keyword(s):  
Electrical Resistivity ◽  
Temperature Dependence ◽  
Spin Relaxation ◽  
Electron Spin ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Striking Similarity ◽  
Relaxation Processes ◽  
Electron Spin Relaxation ◽  
Sodium And Potassium

Electron spin resonance (e. s. r.) spectra of small particles ( ca . 500 nm) of sodium and potassium metals have been recorded over the temperature range 4─100 K. Analysis of the e. s. r. lineshapes yields values of the electron spin-lattice relaxation rate T -1 1 . Both electron spin relaxation and electrical resistivity in the alkalis are governed by the scattering of high velocity conduction electrons by lattice phonons. The temperature dependence of T -1 1 bears a striking similarity to that of the electrical resistivity. In both cases the temperature dependence is adequately described by a Bloch-Grüneisen function for temperatures above ½ θ , where θ is the Debye temperature. If a Debye model is used to approximate the behaviour of lattice vibrational modes, the derived Debye temperatures from the spin relaxation data are about 20% lower in the particulate samples of sodium and potassium than in the corresponding bulk metals.

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