Orientational ordering in solid D/sub 2/ from NMR studies. I. The HCP phase

Journal Article · Wed Oct 01 00:00:00 EDT 1986 · J. Low Temp. Phys.; (United States)

DOI:https://doi.org/10.1007/BF00685401· OSTI ID:6992311

Calkins, M; Banke, R; Li, X; Meyer, H

Using a coherent pulsed NMR spectrometer operating at 5.9 MHz, measurements have been made of the free induction decay and of the solid echo in hcp solid D/sub 2/. From these data, and using Fourier transform techniques, the NMR line shapes and longitudinal relaxation times have been found for both o-D/sub 2/ (angular momentum J = 0 and spin I = 2) and p-D/sub 2/ (with J = 1 and I = 1) separately. The concentration and temperature extended over the ranges 0.05 less than or equal to X(J = 1) less than or equal to 0.56 and 0.04 < T < 3 K, respectively. For both o-D/sub 2/ and p-D/sub 2/, the second moment of the NMR line shape rises smoothly as the temperature decreases, while the relaxation times pass through a minimum. No evidence of a thermal hysteresis could be found in the line shape or relaxation times. The orientational ordering increases continuously as the temperature decreases and the results lead to the conclusion that there is no evidence for a well-defined transition into a phase that has the characteristics of a glassy state, at least above 0.05 K. calculations of the rms order parameter o for p-D/sub 2/ as a function of X and T are presented and the results compared with those for solid H/sub 2/. Above approx. = 0.5 K, the agreement is very good, while below approx. = 0.3 K, o(H/sub 2/)> sigma (D/sub 2/). The orientational polarization of the J = 0 molecules in D/sub 2/ by the surrounding J = 1 molecules is measured from the ratio of the lineshape second moments and is found to be in order-of-magnitude agreement with the predictions by A. B. Harris in the high-temperature limit. An analysis and correlation of the various measured relaxation times via energy diffusion models is presented. From the spin-lattice relaxation times of the J = 1 molecules, the orientational fluctuation rates are estimated for various concentrations as a function of T and compared with the results from H/sub 2/.

• Research Organization: Boeing Aerospace Co., Seattle, WA
• OSTI ID: 6992311
• Journal Information: J. Low Temp. Phys.; (United States), Vol. 65:1/2
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
DEUTERIUM
HCP LATTICES
NMR SPECTRA
ORDER PARAMETERS
CORRECTIONS
HYDROGEN
LINE WIDTHS
NMR SPECTROMETERS
QUANTUM CRYSTALS
RELAXATION TIME
SPIN ORIENTATION
SPIN-LATTICE RELAXATION
TEMPERATURE DEPENDENCE
ULTRALOW TEMPERATURE
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTALS
ELEMENTS
HEXAGONAL LATTICES
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
MEASURING INSTRUMENTS
NONMETALS
NUCLEI
ODD-ODD NUCLEI
ORIENTATION
RELAXATION
SPECTRA
SPECTROMETERS
STABLE ISOTOPES
656002* - Condensed Matter Physics- General Techniques in Condensed Matter- (1987-)