NMR studies of a D/sub 2/ single crystal in the ordered phase

Journal Article · Fri Jul 01 00:00:00 EDT 1988 · J. Low Temp. Phys.; (United States)

DOI:https://doi.org/10.1007/BF00681728· OSTI ID:5894495

Banke, R; Li, X; Clarkson, D; Meyer, H

The authors report the first experimental study of the NMR lineshape anisotropy in the orientationally ordered cubic phase of a D/sub 2/ single crystal. The para-D/sub 2/ concentration covered the range 0.72 < X < 0.82. The observed line shapes were obtained by means of Fourier transform techniques from the solid echoes recorded with a pulsed NMR spectrometer operating at 5.9 MHz. Theoretical line shapes and their second moments for p-D/sub 2/ (with angular momentum J = 1 and spin I = 1) and for o-D/sub 2/ (with J = 0, I = 2) were calculated as a function of the applied field direction from the theory by A.B. Harris. Good agreement was obtained for all directions, provided that, just as for solid H/sub 2/ a Gaussian function for the distribution of molecular axial alignment was assumed with an rms spreading angle of approx. 6 deg for X = 0.77. No change in the anisotropy of the second moment in the disordered phase was detected between the initial (hcp) crystal and after repeated thermal cyclings through the martensitic transition. This result implies no change in the orientation of the plane for the sliding nets during repeated passages through the transition. Furthermore, they report measurements of the longitudinal relaxation time for both p-D/sub 2/ and o-H/sub 2/ versus T over the temperature range 0.5 < T < 3.5 K. The complex behavior reported previously for both H/sub 2/ and D/sub 2/ was confirmed. Measurements of the relaxation times as a function of the applied field direction in the ordered phase at 1.2 K showed no anisotropy within experimental error, and this result is discussed in the light of predictions by Hardy and Berlinsky. Finally, the polarization of the J = 0 molecules is studied as a function of the concentration X of the J = 1 molecules and their state of orientational order over a wide range of X and T in the ordered and disordered states.

• Research Organization: Duke Univ., Durham, NC (USA)
• OSTI ID: 5894495
• Journal Information: J. Low Temp. Phys.; (United States), Vol. 72:1-2
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
DEUTERIUM
NMR SPECTRA
ANISOTROPY
CRYSTAL-PHASE TRANSFORMATIONS
CUBIC LATTICES
FOURIER TRANSFORM SPECTROMETERS
FOURIER TRANSFORMATION
GAUSS FUNCTION
HCP LATTICES
MARTENSITE
MONOCRYSTALS
NMR SPECTROMETERS
ORDER PARAMETERS
ORDER-DISORDER TRANSFORMATIONS
SPIN
SPIN ORIENTATION
THERMAL CYCLING
ULTRALOW TEMPERATURE
ALLOYS
ANGULAR MOMENTUM
CARBON ADDITIONS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTALS
FUNCTIONS
HEXAGONAL LATTICES
HYDROGEN ISOTOPES
INTEGRAL TRANSFORMATIONS
IRON ALLOYS
ISOTOPES
LIGHT NUCLEI
MEASURING INSTRUMENTS
NUCLEI
ODD-ODD NUCLEI
ORIENTATION
PARTICLE PROPERTIES
PHASE TRANSFORMATIONS
SPECTRA
SPECTROMETERS
STABLE ISOTOPES
TRANSFORMATIONS
656002* - Condensed Matter Physics- General Techniques in Condensed Matter- (1987-)