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Measurements of the Leggett Frequency in 3 He-B in Aerogel

Measurements of the Leggett Frequency in 3 He-B in Aerogel. V.V.Dmitriev , V.V. Zavjalov, D.Ye. Zmeev, N.Mulders +. Kapitza Institute, Moscow. University of Delaware, USA. solid 3 He. «A». «B». P (bar). normal phase. T (mK). Conditions of our experiments:. bar. Oe. kHz. w-w L. 0.

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Measurements of the Leggett Frequency in 3 He-B in Aerogel

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  1. Measurements of the Leggett Frequency in3He-B in Aerogel V.V.Dmitriev, V.V. Zavjalov, D.Ye. Zmeev, N.Mulders+ Kapitza Institute, Moscow University of Delaware, USA

  2. solid 3He «A» «B» P (bar) normal phase T (mK) Conditions of our experiments: bar Oe kHz

  3. w-wL 0 b q0 “Usual” bulk 3He-B: Brinkman-Smith mode: w =

  4. Dwmax 0 Low excitation CW NMR in 3He-B: the form of the line is defined by distribution of vector n n

  5. Dwmax 0 Low excitation CW NMR in 3He-B: the form of the line is defined by distribution of vector

  6. Experimental chamber No 1 1 см

  7. Low excitation CW NMR lines in 3He-B in aerogel in different cells for the same conditions

  8. w-wL 0 b q0 “Usual” bulk 3He-B: Brinkman-Smith mode: w =

  9. Initial frequency of the FIDS versus the tipping angle b (degrees)

  10. z The HPD in nonlinear CW NMR z1 zw z2 H0 z2 z1

  11. 0.01 Oe 0.005 Oe 0.002 Oe Signal amplitude Oe z (mm) The HPD in nonlinear CW NMR

  12. H h y x M Spatially homogeneous modes of oscillations of the HPD Rotating frame:

  13. Experimental cell for studies of low frequency HPD oscillations

  14. HPD formation in cell with aerogel Absorption & dispersion 0 H-H0 (Oe) H0=284 Oe, С H=0.2 Oe/cm

  15. H h y x M Spatially homogeneous modes of oscillations of the HPD Rotating frame:

  16. Bulk 3He-B Lock-in output time (ms)

  17. Oscillations frequency vs RF-field amplitude Bulk 3He-B. (W/2p)2 (Hz2) h (mOe)

  18. B-like phase of 3He in aerogel Lock-in output time (ms)

  19. Leggett frequency in bulk 3He-B ( ) and in 3He-B in aerogel ( ) (solid line from: P.J.Hakonen et.al., JLTP, 76, 225 (1989)) WB/2p (kHz) T/Tc, T/Tca

  20. Leggett frequency in 3He in aerogel ( ) for 25.5 bars (solid line is for bulk 3He-B : P.J.Hakonen et.al., JLTP, 76, 225 (1989)) WB/2p (kHz) T/Tc, T/Tca

  21. Leggett frequency in 3He in aerogel ( ) for 25.5 bars (solid line is for bulk 3He-B : P.J.Hakonen et.al., JLTP, 76, 225 (1989)) WB/2p (kHz) T/Tc, T/Tca

  22. absorption (arb. units)

  23. Conclusions: - New mode of the HPD oscillations has been found. It has allowed to measure the Leggett frequency in 3He-B in aerogel - Orienting influence of the boundary “aerogel - bulk 3He” on the texture of and n is different from that known for the the boundary “bulk 3He - wall”

  24. Conclusions: - New mode of the HPD oscillations has been found. It has allowed to measure the Leggett frequency in 3He-B in aerogel - Orienting influence of the boundary “aerogel - bulk 3He” on the texture of and n is different from that known for the the boundary “bulk 3He - wall” is parallel to the boundary “aerogel-bulk 3He”?

  25. Absorption and dispersion z (mm) The HPD in the cell partially filled with aerogel

  26. FIDS from the HPD in the cell partially filled with aerogel amplitude time (s)

  27. WB/2p (kHz) T/Tc, T/Tca

  28. Frequency of oscillations vs amount of aerogel (results of computer simulations of Leggett equations) k0 m1 m2 Frequency (Hz) k1 k2 filling factor cell length=1.8 mm

  29. Free induction decay signal (FIDS) recorded by digital oscilloscope Time (ms)

  30. FIDS amplitude time (ms)

  31. Pure 3He + aerogel: 2 solid monolayers of 3He on surface of aerogel strands: 4He replaces 3He atoms at surface: NMR signal is determined only by liquid 3He

  32. amplitude time (s) FIDS from the HPD with initial length of 4.9 mm

  33. Oe Signal amplitude Oe z (mm)

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