Accession Number:

ADA526004

Title:

NMR Measurements of Power-Law Behavior in the Spin-Wave and Critical Regions of Ferromagnetic EuO

Descriptive Note:

Electronic preprint

Corporate Author:

ARMY COMMUNICATIONS-ELECTRONICS COMMAND FORT MONMOUTH NJ

Report Date:

2010-06-30

Pagination or Media Count:

4.0

Abstract:

Precision continuous-wave NMR measurements have been carried out over the entire magnetization curve of EuO and are presented in tabular form. Two very closely spaced resonances are observed and are attributed to domain and domain-wall signals. Both of the signals are useful for analysis in the spin-wave region. Only the domain signal is measurable above approx. 50K. The latter is used for fitting Tc and the critical exponent Beta. The critical-region fits agree with previous measurements, within experimental error. The low-temperature data exhibit a clear-cut T2 behavior, at variance with the expectations of conventional spin-wave theory. This result is discussed in relation to two semi-empirical spin-wave schemes, one formulated by N. Bykovetz, and one by U. Koebler. The NMR signal at 4.2K gives no indication of a quadrupole splitting, in contradiction to the interpretation of several previous spin-echo NMR spectra observed in EuO. This issue remains unresolved.

Subject Categories:

  • Properties of Metals and Alloys
  • Electricity and Magnetism
  • Atomic and Molecular Physics and Spectroscopy
  • Nuclear Physics and Elementary Particle Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE