Sign of nuclear electric quadrupole coupling constants in solids from γ-ray anisotropy measurements after capture of polarized neutrons

authored by

D. Dubbers, H. Ackermann, M. Grupp, P. Heitjans, H. J. Stöckmann

Abstract

An experimental method is presented which allows the determination of the sign of nuclear electric quadrupole interactions in solids. Activated target nuclei with a purely dipolar spin polarization are produced by capture of polarized thermal neutrons. The quadrupole coupling of the nuclei to the electric field gradient tensor in the target crystal converts this (dipolar) polarization partly into a (quadrupolar) alignment, which can be measured by the anisotropy of the γ-ray emission in a succeeding nuclear transition. The sign of the alignment created in this reorientation process depends on the sign of the electric quadrupole interaction. The reorientation effect can be enhanced by selective induction of nuclear magnetic resonance transitions. The method has been applied to measure the sign of the crystal electric field gradient (efg) in tetragonal MgF₂. Further, the sign of an efg in cubic CaF₂ originating from a¹⁹F interstitial adjacent to the activated²⁰F probe nucleus has been determined. The method is in principle applicable to a considerable number of nuclides.

External Organisation(s)

Heidelberg University
Institut Laue-Langevin

Type

Article

Journal

Zeitschrift für Physik B Condensed Matter and Quanta

Volume

25

Pages

363-368

No. of pages

6

ISSN

0340-224X

Publication date

12.1976

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials, Condensed Matter Physics

Electronic version(s)

https://doi.org/10.1007/BF01315252 (Access: Unknown)