Spin-wave instabilities in {sup 3}He-{sup 4}He solutions at high magnetic field

Journal Article · Wed Nov 01 04:00:00 EST 1995 · Journal of Low Temperature Physics

DOI:https://doi.org/10.1007/BF00753399· OSTI ID:183455

Koenig, R; Ager, J H; Bowley, R M ^[1]

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1. Univ. of Nottingham (United Kingdom); and others

During our recent high field pulsed NMR experiments on a spin-polarized saturated {sup 3}He-{sup 4}He solution, we observed a long-lived oscillating signal in addition to the usual spin-echo. The oscillations were excited by the application of a single RF tipping pulse of angle greater than some critical value. They were observable only for temperatures below 20mK corresponding to values of the spin-rotation parameter {mu}M{sub 0}{ge}3. The signals were not present during experiments on lower concentration solutions. The frequencies of the oscillations were found to scale as the cosine of the tipping angle. The nature and shape of the oscillations suggest that they may be driven by instabilities through a mechanism proposed by Castaing. These instabilities arise due to a modification of the non-linear term in the Leggett equation by the large magnetization gradients present at the edges of the pulsed region.

• Sponsoring Organization: USDOE
• OSTI ID: 183455
• Report Number(s): CONF-950676--; CNN: Grant DMR-9412769
• Journal Information: Journal of Low Temperature Physics, Journal Name: Journal of Low Temperature Physics Journal Issue: 3-4 Vol. 101; ISSN JLTPAC; ISSN 0022-2291
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
66 PHYSICS
HELIUM 3
HELIUM 4
INSTABILITY
MAGNETIC FIELDS
MIXTURES
NUCLEAR MAGNETIC RESONANCE
SPIN ECHO
SPIN ORIENTATION
SPIN WAVES