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Journal of Low Temperature Physics

, Volume 82, Issue 5–6, pp 369–380 | Cite as

NQR spin-echo methods at very low temperatures

  • I. P. Goudemond
  • J. M. Keartland
  • M. J. R. Hoch
Article

Abstract

Pulsed methods may be successfully used in very low temperature NMR or NQR experiments provided good thermal anchoring of the sample is achieved. In order to reduce heating effects, it is advantageous to use rf pulses that are shorter than the standard magnetization tipping pulses used at higher temperatures. The present work describes the use of short nonstandard rf pulses in NQR spin-echo experiments on powdered samples. Theoretical density matrix calculations have been carried out, and the resulting expression for the echo amplitude confirmed by experiment. Measurements were made on a powder sample of high-purity semimetallic arsenic using a sample probe designed for use in a dilution refrigerator. Preliminary spin-lattice relaxation-time measurements show that the Korringa relation holds in arsenic down to 150 mK.

Keywords

Arsenic Density Matrix Sample Probe Heating Effect Theoretical Density 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Plenum Publishing Corporation 1991

Authors and Affiliations

  • I. P. Goudemond
    • 1
  • J. M. Keartland
    • 1
  • M. J. R. Hoch
    • 1
  1. 1.Condensed Matter Physics Research Unit, Department of PhysicsUniversity of the WitwatersrandJohannesburgSouth Africa

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