Rotating-frame nuclear spin-lattice relaxation due to the motion-induced time variation of quadrupolar and dipolar interactions in crystals

Wolf, D.

doi:10.1103/physrevb.14.932

Cited by 7 publications

(4 citation statements)

References 16 publications

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“…B m can also be calculated theoretically for any particular model of molecular motion and thus a test of any assumed model can be applied quite rigorously. This has been done, for example, in the case of ionic diffusion on a fluorite crystal lattice due to a vacancy mechanism [175,176] and used to interpret T 1 measurements for 19 F in BaF 2 (figure 16) made over a wide temperature range (300 to 1300 K).…”

Section: Spin-lattice Relaxation (T 1 )mentioning

confidence: 99%

NMR techniques in materials physics: a review

Smith

Strange

1996

Meas. Sci. Technol.

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Nuclear magnetic resonance (NMR) has progressed rapidly over the last decade as a result of improved experimental technology and development of novel approaches. In this review a brief introduction to NMR interactions and relaxation processes is given to allow an appreciation of the experimental developments. The underlying physical principles of the latest NMR methodology for probing solid materials are stressed. Techniques covered include pulse Fourier transform with emphasis on the difficulties of recording broad resonances and strategies for overcoming them. Selective experiments such as polarization transfer are included. The major impetus given to NMR spectroscopy by improved resolution through line-narrowing methods is detailed. Advanced methods such as multiple quantum and two-and three-dimensional spectroscopy are also discussed. NMR as a probe of microscopic dynamic behaviour through relaxation and direct diffusion measurements over a wide temperature range is examined. Recent developments in magnetic resonance imaging that now offer the possibility of non-destructive investigation of materials are presented. Dr M E Smithhas been interested in solid state NMR for over a decade. He learnt the art from Professor R Dupree, graduating with a PhD from the University of Warwick in 1988 and has subsequently held appointments with Bruker Analytische Messtechnik and CSIRO Division of Materials Science in Melbourne as a physicist specializing in solid state NMR. He was appointed lecturer in the Physics Department at the University of Kent in 1992 and is now Reader in Solid State NMR, where his main research interest is to develop NMR into an accepted technique for materials characterization.

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Section: Spin-lattice Relaxation (T 1 )mentioning

confidence: 99%

NMR techniques in materials physics: a review

Smith

Strange

1996

Meas. Sci. Technol.

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“…Furthermore, the additional assumption that the actual jump time of a nucleus is so short that all spins have the same orientation just after the jump as they had before leads to the "sudden" quantum approximation used in the SARF theory. Wolf [5] has derived in a well-confirmed theory general expressions without these restrictions for the rotating-frame relaxation rate due to the motion-induced time variation of quadrupolar and dipolar spin interactions. I n the limiting case of strong collisions, the quadrupolar part of the relaxation rate with which we are concerned here is given bv where H I is the strength of the locking field in the rotating-frame experiment, H , is the local dipolar field and HQ is the total quadrupolar field, which in the case of lattices with cubic point symmetry results from the presence of lattice defects.…”

Section: Quadmcpolar Relaxation Rate In the Strong-collision Regionmentioning

confidence: 99%

“…The frequency o1 at the maximum of the function is given by 2wp, = 1 . (36) If the locking field H I is only of the order of magnitude of the local field H , = = [ H g + HG]1/2 [5] in (26), w1 must be replaced by the more general expression for the frequency…”

Section: Quadrupolar Relaxation Rate In the Weak-collisiotb Regionmentioning

confidence: 99%

“…(i) Starting from the more general theory of Wolf [5] we present a calculation of the relevant quadrupolar part of the rotating-frame relaxation rate induced by the motion of dislocations without any limitations in the mean time of stay t. To do this a modified model of thermally activated, jerky motion of dislocations as given by Argon [6] is introduced into the relaxation theory, where the behaviour in time of the motion of a given dislocation is regarded as a Markov process and the distribution of the step width of the dislocation between the random distributed line obstacles is given by a Gaussian function.…”

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Determination of the velocity of mobile dislocations by nuclear spin relaxation measurements

Hackelöer

Selbach

Kanert

et al. 1977

Physica Status Solidi (b)

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(a), H. SELBACH (a), 0. KANERT (a), A. W. SLEESwYK (b), and G . HUT (b) Wolf's general theory of rotating-frame nuclear spin-lattice relaxation is applied to the effect caused by dislocations moving at an average velocity V. Equations are presented for the dependence of the NMR relaxation rate Rg) on the mean waiting time T of a dislocation before a n obstacle, valid in both the weak-and the strong-collision regions. In the latter the Slichter-Ailion-RowlandFradin theory applies. Nuclear spin relaxation tests on 23NaCl and 23NaF single crystals deformed at constant strain rates E confirm the theory. The experimental data for the predicted maximum in Rg) (reached only for NaCl at k, = 20 s-l) yield directly rm = 2.8 x 8 , the mobile fraction of dislocations em/et = 0.26. The value of r,, together with the mean distance between obstacles of e 2 x 10-4 cm, derived from the slope of the curve in the strong-collision region, leads t o w, = 7.1 cm s-l, corresponding t o a mobile dislocation density em = 1.4 x lo8 cm-2.Ausgehend von der allgemeinen Theorie der Kernspinrelaxation im rotierenden System von Wolf wurde die Relaxation durch Versetzungen untersucht, die sich mit einer mittleren Geschwindigkeit 'i, bewegen. Die hier formulierten Gleichungen beschreiben die Abhiingigkeit der NMRRelasationsrate R g ) von der mittleren Wartezeit T einer Versetzung vor einem Hindernis somohl fur den ,,weak-collision"-als auch fiir den ,,strong-collision"-Bereich, in welchem die SlichterAilion-Rowland-Fradin-Theorie anwendbar ist. Die theoretischen Beziehungen werden bestiitigt durch Kernspinrelaxationszeitmessungen an "NaCl-und WaF-Einkristallen, die mit konstanter Kompressionsrate k plastisch verformt wurden. Aus dem esperirnentellen Wert fur das erwartete Maximum in Rg) (nur erreicht fur NaCl bei: k, = 20 s-l) ergibt sich direkt: t , = 2,8 * sec;Bruchteil der mobilen Versetzungen: em/et FZ 0,26. Zusammen mit eineni mittleren Abstand zwischen den Hindernissen von ca. 2 * cm, der sich aus der Steigung der Kurve irn ,.strongcollision"-Bereich ergibt, erhalt man ; , = 7,l cm sec-', entsprechend einer Dichte der bcweglichen Versetzungen von em = 1,4 * lo8 cm-*.

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Diffusion in Rare Gas Solids

Norberg

2007

Encyclopedia of Magnetic Resonance

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Rotating-frame nuclear spin-lattice relaxation due to the motion-induced time variation of quadrupolar and dipolar interactions in crystals

Cited by 7 publications

References 16 publications

NMR techniques in materials physics: a review

NMR techniques in materials physics: a review

Determination of the velocity of mobile dislocations by nuclear spin relaxation measurements

Diffusion in Rare Gas Solids

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