Nuclear spin-lattice relaxation in metals at low temperatures
In NMR experiments performed on metals at low temperatures, the analysis to obtain the nuclear spin-lattice relaxation time tau/sub 1/ can be quite complicated. The electronic heat capacity ultimately becomes less than that of the nuclear spins, and the characteristic times for heat flow through the various resistances between the nuclear spins and the thermal bath can become long relative to tau/sub 1/. This makes it necessary to solve the full set of coupled differential equation describing the thermal relaxation. This problem has been examined because tau/sub 1/ is used as a thermometric parameter, and the authors consider the cases when the radiofrequency field penetrates the sample completely (powders and foils) and when only the skin-depth nuclei are excited (bulk specimens). Using our theoretical model, the authors analyze experimental results for platinum powder and a thallium bulk sample and obtain consistent values for kappa = tau/sub 1/T over a wide range of experimental conditions, even when thermal bottlenecks occur and the apparent relaxation time is much longer than tau/sub 1/. These values are kappa(Pt) = (34.2 +/- 0.6) x 10/sup -3/ sec K and kappa(Tl) = (4.37 +/- 0.08) x 10/sup -3/ sec K.
- Research Organization:
- Technical Univ. of Munich and Walther Meissner Institute, Garching (Germany, F.R.)
- OSTI ID:
- 6852368
- Journal Information:
- J. Low Temp. Phys.; (United States), Vol. 70:1-2
- Country of Publication:
- United States
- Language:
- English
Similar Records
TU-EF-BRA-02: Longitudinal Proton Spin Relaxation and T1-Imaging
Spontaneous nuclear ferromagnetic ordering of In nuclei in AuIn{sub 2}. Part I. Nuclear specific heat and nuclear susceptibility
Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
METALS
NUCLEAR MAGNETIC RESONANCE
RELAXATION TIME
SPIN-LATTICE RELAXATION
DIFFERENTIAL EQUATIONS
ELECTRONIC SPECIFIC HEAT
HEAT FLOW
HELIUM 3
MAGNETIC MOMENTS
MAGNETIC SUSCEPTIBILITY
MATHEMATICAL MODELS
PLATINUM
SPIN
TEMPERATURE DEPENDENCE
THALLIUM
ULTRALOW TEMPERATURE
ANGULAR MOMENTUM
ELEMENTS
EQUATIONS
EVEN-ODD NUCLEI
HELIUM ISOTOPES
ISOTOPES
LIGHT NUCLEI
MAGNETIC PROPERTIES
MAGNETIC RESONANCE
NUCLEI
PARTICLE PROPERTIES
PHYSICAL PROPERTIES
PLATINUM METALS
RELAXATION
RESONANCE
SPECIFIC HEAT
STABLE ISOTOPES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENTS
656002* - Condensed Matter Physics- General Techniques in Condensed Matter- (1987-)