Magnetic Phase Transition in a Nanonetwork of Solid<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi>He</mml:mi><mml:mprescripts /><mml:none /><mml:mn>3</mml:mn></mml:mmultiscripts></mml:math>in Aerogel

Bradley, D. I.; Fisher, S. N.; Guénault, A. M.; Haley, R. P.; Mulders, N.; Pickett, G. R.; Potts, Diane; Skyba, P.; Smith, J.G.; Tsepelin, V.; Whitehead, R. C. V.

doi:10.1103/physrevlett.105.125303

Cited by 6 publications

(5 citation statements)

References 21 publications

(38 reference statements)

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“…When using pure 3 He, in cw NMR experiments we detect a strong paramagnetic signal from solid 3 He on the aerogel surface (similar to experiments with 3 He in silica aerogels [30,31]). In order to remove solid 3 He from the surface, in Setup 1 we added 4 He (1.3 or 1.7 mmole) into the empty cell at temperatures T ≤ 100 mK and then filled the cell with 3 He.…”

Section: Methodssupporting

confidence: 78%

Polar Phase of $$^3$$He in Nematic Aerogel and Quartz Tuning Fork as Sensitive Detectors of Surface Boundary Conditions

et al. 2022

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A new superfluid phase of 3 He, a polar phase, which is known to stabilize in nematic aerogel, has already led to observation of many new phenomena. One important condition for existence of the polar phase is a 4 He coverage, which removes solid paramagnetic 3 He from the surface of the aerogel strands. We report here the results of NMR experiments with superfluid 3 He in nematic aerogel demonstrating influence of 4 He coverage. Simultaneous measurements of resonance properties of a quartz tuning fork immersed in liquid 3 He well correlate with the NMR data.

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Section: Methodssupporting

confidence: 78%

Polar Phase of $$^3$$He in Nematic Aerogel and Quartz Tuning Fork as Sensitive Detectors of Surface Boundary Conditions

et al. 2022

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“…The warming transitions shown in Fig. 3 have quadratic field dependence, as expected from Ginzburg-Landau theory 23,24 , precisely mimicked by cooling transitions that supercool by The liquid susceptibility was obtained after subtracting the contribution from the several layers of solid 3 He adsorbed to the surface of aerogel, well known to have a Curie-Weiss temperature dependence 13,21,30 . The jump in susceptibility on cooling or warming marks first-order transitions, T AB (T BA ).…”

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confidence: 69%

The superfluid glass phase of 3He-A

Pollanen

Zimmerman

et al. 2013

Nature Phys

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It is established theoretically that an ordered state with continuous symmetry is inherently unstable to arbitrarily small amounts of disorder 1,2. This principle is of central importance in a wide variety of condensed systems including superconducting vortices 3,4 , Ising spin models 5 and their dynamics 6 , and liquid crystals in porous media 7,8 , where some degree of disorder is ubiquitous, although its experimental observation has been elusive. On the basis of these ideas, it was predicted 9 that 3 He in high-porosity aerogel would become a superfluid glass. We report here our nuclear magnetic resonance measurements on 3 He in aerogel demonstrating destruction of long-range orientational order of the intrinsic superfluid orbital angular momentum, confirming the existence of a superfluid glass. In contrast, 3 He-A generated by warming from superfluid 3 He-B has perfect long-range orientational order providing a mechanism for switching off this effect. Close to the absolute zero of temperature, liquid 3 He condenses into a p-wave superfluid of Cooper pairs resulting in two phases with fundamentally different symmetry: the isotropic B-phase and an anisotropic A-phase. In zero magnetic field, 3 He-A appears in a small corner of the pressure versus temperature phase diagram shown in Fig. 1d. Its anisotropy, a paradigm for more recently discovered unconventional superconductors 10 , is characterized by the orientation of its order parameter defined by orbital angular momentum and spin induced by magnetic field,l andŝ. The spin is necessarily aligned with an applied magnetic field, H; however, the orbital angular momentum has continuous rotational symmetry. That symmetry can be broken, for example, at a wall or interface to whichl must be perpendicular, thereby defining a preferred direction on a macroscopic scale. Volovik proposed 9 that this long-range orientational coherence of angular momentum would be destroyed by random microscopic disorder that can be realized if the 3 He is imbibed in highly porous silica aerogel as shown in our simulation Fig. 1a,b. This sensitivity to small amounts of disorder on a microscopic scale was discussed by Larkin 1 and Imry and Ma 2 for a broad range of physical phenomena 3-8 and we refer to this as the LIM effect. If this proposal is correct then in the LIM state the order parameter structure of the superfluid will be completely hidden, a behaviour of potential significance for understanding exotic superconductors such as URu 2 Si 2 (ref. 11). We use nuclear magnetic resonance (NMR) to look for the LIM state of superfluid 3 He-A, directly interrogating the orientation of l by measuring the Leggett shift 12 of the NMR spectrum, ω A. In pure 3 He this frequency shift is proportional to the nuclear dipole energy, F D ∝ −(l •d) 2 , whered is a spin-space vector constrained to be perpendicular toŝ while minimizing F D. This shift is strongly temperature dependent, but for an orbital glass it should be very small, or ideally zero (Supplementary Information) as we report here.

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“…By applying external magnetic field B = (0, 0, B 0 + B rem ) = (0, 0, B), the magnetic moment M 0 is formed on the fork's horizontal surfaces. The magnetic moment M 0 of the surface layer includes the strong spin anisotropy of the superfluid 3 He layer together with magnetic moments of solid 3 He atoms covering the fork's surface [5,[26][27][28][29]. However, based on measurements presented in [26], we presume that magnetic moments of solid 3 He atoms behave as a paramagnet and, on a time scale of the fork oscillation period, its Zeeman energy is always minimized.…”

Section: Experimental Results and Analysismentioning

confidence: 97%

“…The magnetic moment M 0 of the surface layer includes the strong spin anisotropy of the superfluid 3 He layer together with magnetic moments of solid 3 He atoms covering the fork's surface [5,[26][27][28][29]. However, based on measurements presented in [26], we presume that magnetic moments of solid 3 He atoms behave as a paramagnet and, on a time scale of the fork oscillation period, its Zeeman energy is always minimized. Therefore, magnetic property of the surface layer of superfluid 3 He-B is responsible for the anisotropy of the magnetic moment M. According to [5], the anisotropic spin susceptibility of the surface layer of superfluid 3 He-B at T→0 can be expressed as…”

Section: Experimental Results and Analysismentioning

confidence: 97%

“…However, the open question is an influence of the solid 3 He on this phenomenon. Although we assumed a paramagnetic property of the solid 3 He layer, the magnetic susceptibility of the solid 3 He dominates at ultra low temperatures [26]. An influence of solid 3 He could be tested by using 4 He as a coverage on the surface of the tuning fork, since 4 He atoms remove 3 He atoms from the surface.…”

Section: Discussionmentioning

confidence: 99%

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NMR-like effect on Anisotropic Magnetic Moment of Surface Bound States in Topological Superfluid $^3$He-B

Clovecko,

Gazo,

Skyba

et al. 2018

Preprint

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We present experimental observation of a new phenomenon, that we interpret as NMR-like effect on anisotropic magnetic moment of the surface Andreev bound states in topological superfluid 3 He-B at zero temperature limit. We show that an anisotropic magnetic moment formed near the horizontal surface of a mechanical resonator due to symmetry violation of the superfluid 3 He-B order parameter by the resonator's surface may lead to anomalous damping of the resonator motion in magnetic field. In difference to classical NMR technique, here NMR was excited using own harmonic motion of the mechanical resonator, and nuclear magnetic resonance was detected as a maximum in damping when resonator's angular frequency satisfied the Larmor resonance condition.

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Magnetic Phase Transition in a Nanonetwork of SolidHe3in Aerogel

Cited by 6 publications

References 21 publications

Polar Phase of $$^3$$He in Nematic Aerogel and Quartz Tuning Fork as Sensitive Detectors of Surface Boundary Conditions

Polar Phase of $$^3$$He in Nematic Aerogel and Quartz Tuning Fork as Sensitive Detectors of Surface Boundary Conditions

The superfluid glass phase of 3He-A

NMR-like effect on Anisotropic Magnetic Moment of Surface Bound States in Topological Superfluid $^3$He-B

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