Triplet spin-lattice relaxation rates from spin-echo saturation recovery

1981 ◽  
Vol 44 (2) ◽  
pp. 348-354 ◽  
Author(s):  
D.C Doetschman ◽  
B.J Botter
Keyword(s):  
Spin Echo ◽  
Lattice Relaxation ◽  
Saturation Recovery ◽  
Spin Lattice Relaxation ◽  
Relaxation Rates ◽  
Spin Lattice

89Y NMR SPECTRA AND RELAXATION IN UNDERDOPED AND OVERDOPED REGIMES OF SUPERCONDUCTING Ca-DOPED YBCO6 AND YBCO7

2003 ◽  
Vol 17 (04n06) ◽  
pp. 791-798
Author(s):  
P. CARRETTA ◽  
A. LASCIALFARI ◽  
A. RIGAMONTI ◽  
P. TEDESCO ◽  
F. TEDOLDI
Keyword(s):  
Knight Shift ◽  
Nmr Spectra ◽  
Spin Echo ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Relaxation Rates ◽  
Spin Lattice ◽  
Antiferromagnetic Correlation ◽  
Experimental Findings

The results of a study of 89 Y NMR line shape and Knight shift, of the spin-echo dephasing time and of spin lattice relaxation time in Ca-doped YBCO compounds are presented. The underdoped and the overdoped regimes are achieved by means of Ca 2+ for Y 3+ substitutions in the parent antiferromagnet YBa 2 Cu 3 0 6.1 and in the chain-full YBa 2 Cu 3 0 7, respectively. The experimental findings are discussed in the light of models of localized Cu 2+ electrons and of delocalized Fermi-like carriers with antiferromagnetic correlation. Insights are obtained in regards of the density of states evolution with doping and of the occurrence, in the underdoped regime, of low-energy magnetic excitations causing a divergence of the relaxation rates on cooling, accompanied by a concurrent broadening of the NMR line. It is argued how a revision of the commonly accepted view for the microscopic magnetic properties in the YBCO family is required in order to attain a comprehensive justification of the variety of experimental data.

Analysis of Spin Polarisation Transients in Periodically Photo-excited Triplet States

1975 ◽  
Vol 30 (5) ◽  
pp. 571-582 ◽  
Author(s):  
C. J. Winscom
Keyword(s):  
Lattice Relaxation ◽  
Rectangular Pulse ◽  
Decay Rates ◽  
Spin Lattice Relaxation ◽  
Pulse Excitation ◽  
Triplet States ◽  
Relaxation Rates ◽  
Spin Sublevel ◽  
Spin Lattice ◽  
The Individual

Abstract The behaviour of spin sublevel populations with time following periodic photo-excitation is ex-amined. The treatment is limited to conditions of magnetic field strength and temperature for which the spin lattice relaxation rates dominate the individual spin sublevel decay rates. The response of the system to three modes of excitation is considered: (i) continuous excitation using a time-independent intensity (ii) periodic rectangular pulse excitation and (iii) periodic waveform excitation. A convenient correspondence between the various forms of solutions is pointed out. The requirements of an experiment to determine spin-lattice relaxation rates in organic triplets at 77 K are discussed.

Anion reorientations and cation diffusion in a carbon-substituted sodium nido-borate Na-7,9-C2B9H12: 1H and 23Na NMR studies

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Alexander V. Skripov ◽  
Olga A. Babanova ◽  
Roman V. Skoryunov ◽  
Alexei V. Soloninin ◽  
Terrence J. Udovic
Keyword(s):  
Lattice Relaxation ◽  
Activation Energies ◽  
Spin Lattice Relaxation ◽  
Relaxation Rates ◽  
Cation Diffusion ◽  
Relaxation Data ◽  
Nmr Studies ◽  
Spin Lattice ◽  
Jump Rate ◽  
Disordered Phase

Abstract Polyhydroborate-based salts of lithium and sodium have attracted much recent interest as promising solid-state electrolytes for energy-related applications. A member of this family, sodium dicarba-nido-undecahydroborate Na-7,9-C2B9H12 exhibits superionic conductivity above its order-disorder phase transition temperature, ∼360 K. To investigate the dynamics of the anions and cations in this compound at the microscopic level, we have measured the 1H and 23Na nuclear magnetic resonance (NMR) spectra and spin-lattice relaxation rates over the temperature range of 148–384 K. It has been found that the transition from the low-T ordered to the high-T disordered phase is accompanied by an abrupt, several-orders-of-magnitude acceleration of both the reorientational jump rate of the complex anions and the diffusive jump rate of Na+ cations. These results support the idea that reorientations of large [C2B9H12]− anions can facilitate cation diffusion and, thus, the ionic conductivity. The apparent activation energies for anion reorientations obtained from the 1H spin-lattice relaxation data are 314 meV for the ordered phase and 272 meV for the disordered phase. The activation energies for Na+ diffusive jumps derived from the 23Na spin-lattice relaxation data are 350 and 268 meV for the ordered and disordered phases, respectively.

An experimental evaluation of simplified procedures for determining the proton spin–lattice relaxation rates of natural products

1980 ◽  
Vol 58 (19) ◽  
pp. 2016-2023 ◽  
Author(s):  
Lawrence D. Colebrook ◽  
Laurance D. Hall
Keyword(s):  
Natural Products ◽  
Lattice Relaxation ◽  
Null Point ◽  
Proton Spin ◽  
Computational Method ◽  
Spin Lattice Relaxation ◽  
Relaxation Rates ◽  
Spin Lattice ◽  
Simplified Procedures

A general discussion is given of the determination of the proton spin–lattice relaxation rates of natural products, with particular emphasis on use of the null-point method which, for the systems studied here, gives identical results with those obtained via the conventional (and relatively time consuming) computational method.

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