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We have measured the melting pressure and pressure in the liquid at constant density of ultra-pure 4 He (0.3 ppb of 3 He impurities) with the accuracy of about 0.5 µbar in the temperature range from 10 to 320 mK. Our measurements show that the anomaly on the melting curve below 80 mK which we have recently observed [1] is entirely due to an anomaly in the elastic modulus of Be-Cu from which our pressure gauge is made of. We thus conclude that the melting pressure of 4 He follows the T 4 law due to phonons in the whole temperature range from 10 to 320 mK without any sign of a supersolid transition.Recent experimental results obtained by Kim and Chan [2,3] have revived great interest to the problem of supersolidity which was first discussed almost 40 years ago [4,5,6]. The supersolid state of matter is characterized by the coexistence of crystalline order and superfluidity. In helium crystals, according to Andreev and Lifshitz [4] and Chester [5], quantum delocalization of point defects (most probably -vacancies) might decrease their activation energy to zero. Bose condensation of such defects can lead then to superfluidity in a crystal, that is, supersolidity. During 1970s and 1980s many experimental groups tried to detect this possible supersolid state by various methods, but unsuccessfully (see [7] for a review).

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“…3 He melting pressure was converted to temperature according to the Provisional Low Temperature Scale, PLTS-2000 [27].…”

Section: Cell Thementioning

confidence: 99%

Absence of low-temperature anomaly on the melting curve of 4He

Todoshchenko¹,

Alles²,

Junes³

et al. 2007

Jetp Lett.

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“…The current International Temperature Scale (ITS-90, [2]) extends upwards from 0.65 K to the highest temperature practicably measurable. In year 2000 the ITS-90 was supplemented by the Provisional Low Temperature Scale (PLTS-2000, [3]), which covers the temperature range from 0.9 mK to 1 K. The goal of this paper is twofold:…”

Section: Introductionmentioning

confidence: 99%

“…This range of the ITS-90 was realized at NMi-VSL in 1997. The pressure of 3 He and 4 He, contained in a copper reservoir within a 3 He evaporation cryostat, was measured by using a combination of a gas-operated pressure balance and a capacitive diaphragm gauge at room temperature (see [4]). …”

Section: Introductionmentioning

confidence: 99%

“…4 He interpolating constant volume gas thermometer for the ITS-90 range 3 K to 24.5 K (2007) Between 3.0 K and 24.5561 K, the ITS-90 is defined by means of a helium interpolating constantvolume gas thermometer (ICVGT) calibrated, using specified interpolation equations, at three defining fixed points: 1) the triple point of neon (24.5561 K), 2) the triple point of equilibrium hydrogen (13.8033 K), 3) a temperature between 3.0 K and 5.0 K to be determined using a 3 He or a 4 He vapour pressure termometer.…”

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confidence: 99%

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Traceable low and ultra-low temperatures in The Netherlands

Peruzzi

Bosch²

2009

J. Phys.: Conf. Ser.

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Abstract. The basis for worldwide uniformity of low and ultra-low temperature measurements is provided by two international temperature scales, the International Temperature Scale of 1990 (ITS-90) for temperatures above 0.65 K and the Provisional Low Temperature Scale of 2000 (PLTS-2000) for temperatures in the range 0.9 mK to 1 K. Over the past 10 years, the thermometry research in the Netherlands provided substantial contributions to the definition, realization and dissemination of these scales. We first give an overview of the Dutch contributions to the ITS-90 realization: a) 3 He and 4 He vapour pressure thermometer range of the ITS-90, 0.65 K to 4 K (1997), b) 4 He interpolating constant volume gas thermometry for the ITS-90 range 3 K to 24.5 K (2007) and c) cryogenic fixed points for the ITS-90 range 13.8 K to 273.16 K (2005). Then we highlight our work on 3 He melting pressure thermometry from 10 mK to 1 K (2003) to support the dissemination of the PLTS-2000. Finally we present the current status of the Dutch calibration facilities and dissemination devices providing for traceable low and ultra-low temperatures for use in science and industry: a) the NMi-VSL cryogenic calibration facility for the range 0.65 K to 273.16 K and b) the SRD1000 superconductive reference devices for the range 10 mK to 1 K.

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“…The nuclear stage contains 92 mol of copper (effectively 46 mol in 8 Tesla) along with 5 mol of PrNi 5 [7]. The temperature was monitored using a melting pressure thermometer in the low magnetic field region [8], supplemented by a Kapton capacitance thermometer inside the sample cell. The capacitance thermometer was calibrated in high B/T conditions in an earlier experiment at much higher x 3 = 3.8% [9], in which the viscosity was nearly field independent and could be used as a high B/T thermometer.…”

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confidence: 99%

Giant Viscosity Enhancement in a Spin-Polarized Fermi Liquid

et al. 2007

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The viscosity is measured for a Fermi liquid, a dilute 3 He-4 He mixture, under extremely high magnetic field/temperature conditions (B ≤ 14.8 T, T ≥ 1.5 mK). The spin splitting energy µB is substantially greater than the Fermi energy kBTF ; as a consequence the polarization tends to unity and s-wave quasiparticle scattering is suppressed for T ≪ TF . Using a novel composite vibratingwire viscometer an enhancement of the viscosity is observed by a factor of more than 500 over its low-field value. Good agreement is found between the measured viscosity and theoretical predictions based upon a t-matrix formalism.

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Cited by 108 publications

References 11 publications

Absence of low-temperature anomaly on the melting curve of 4He

Absence of low-temperature anomaly on the melting curve of 4He

Traceable low and ultra-low temperatures in The Netherlands

Giant Viscosity Enhancement in a Spin-Polarized Fermi Liquid

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