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International temperature scales define several fixed points, which temperature values are determined with a very high precision. Some of them, which are in a low-temperature range, are called gaseous fixed points because the reference substances under a normal condition -in a room-temperature range -appear in a gaseous state. These reference substances are called by physicists cryocrystals or quantum crystals when occurring in a low temperature in a solid state. The substances play an important role in a standard thermometry. The triple point of argon, oxygen, neon and hydrogen are primary fixed points of the International Temperature Scale of 1990 (ITS-90) [1]. The triple points of nitrogen, methane and carbon dioxide are secondary fixed points of the scale [2]. Also, the solid-solid phase transitions in the cryocrystals are secondary fixed points of the scale. The highest accuracy methods of measurements applied in a standard thermometry enable the determination with a very small uncertainty of the phase transition temperatures, its reproducibility and stability. The reproducibility and stability of the transition temperature are the most important factors deciding about usefulness of these points in thermometry. Using the highest accuracy methods, better than 1 mK, which at present are used in metrology only can give a new information about nature and properties of investigated substances important also for physicists. PACS: 64.60.Ej Studies/theory of phase transitions of specific substances; 64.75.-g Phase equilibria; 67.90.+z Other topics in quantum fluids and solids.

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“…In the low-temperature range, the International [4][5][6][7] and results of the measurements are presented in this paper.…”

Section: Temperature Scalementioning

confidence: 99%

Cryocrystal phase transitions applied as temperature standards

Szmyrka-Grzebyk

Kowal

2009

Low Temperature Physics

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“…Near the phase boundaries of solid oxygen, the absolute error of T can be recalibrated by T βγ = 43.8 K and T αβ = 23.9 K where heat capacity diverges. These values are recommended for the thermometric fixed points [12].…”

Section: Methodsmentioning

confidence: 99%

α−β and β−γ phase boundaries of solid oxygen observed by adiabatic magnetocaloric effect

et al. 2017

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The magnetic-field-temperature phase diagram of solid oxygen is investigated by the adiabatic magnetocaloric effect (MCE) measurement with pulsed magnetic fields. Relatively large temperature decrease with hysteresis is observed at just below the β-γ and α-β phase transition temperatures owing to the field-induced transitions. The magnetic field dependences of these phase boundaries are obtained as T βγ (H) = 43.8 − 1.55 × 10 −3 H 2 K and T αβ (H) = 23.9 − 0.73 × 10 −3 H 2 K. The magnetic Clausius-Clapeyron equation quantitatively explains the H dependence of T βγ , meanwhile, does not T αβ . The MCE curve at T βγ is of typical first-order, while the curve at T αβ seems to have both characteristics of first-and second-order transitions. We discuss the order of the α-β phase transition and propose possible reasons for the unusual behavior.

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“…This fractional deviation was also seen for the ␤ − ␥ transition. We therefore adopted the position of Szmryka-Grzebyk et al 16 that the two phase transitions should be taken as fixed points at 23.867 and 43.796 K, respectively, for the ␣ − ␤ and ␤ − ␥ transitions and used these fixed points to recalibrate the thermometer reading. All the temperatures given in the figures correspond to this recalibration.…”

Section: Experimental Measurementsmentioning

confidence: 99%

“…The order of the transition is still not agreed upon. 16 Stephens and Majkrzak 7 reported hysteresis for the temperature dependence of the magnetization, and Giauque and Johnston, 17 Orlova, 18 and Ancsin 19 reported evidence for a latent heat. Monte Carlo calculations using deformable cells 1 and calculations of densities for different structures 5 show abrupt changes at the ␣ − ␤ transition.…”

Section: Introductionmentioning

confidence: 99%

Thermal hysteresis of the dielectric susceptibility of solid oxygen in the audio frequency range

Pilla¹,

Hamida

Muttalib

et al. 2008

Phys. Rev. B

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High sensitivity measurements of the dielectric constant of solid oxygen are reported for 4 Ͻ T Ͻ 54 K. The results show unexpectedly large hysteresis effects for the temperature dependence of the dielectric constant in the ␣ and ␤ phases of oxygen on thermal cycling below 44 K. The behavior is compared to that observed for solid N 2 -Ar mixtures where the geometrical frustration of the molecular orientational ordering leads to pronounced memory effects. In contrast to solid N 2 -Ar where the effects of frustration and disorder combine to form an orientational glass, there is no disorder present for pure O 2 and the hystereses are attributed to the strong frustration of the interactions.

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Cited by 14 publications

References 4 publications

Cryocrystal phase transitions applied as temperature standards

Cryocrystal phase transitions applied as temperature standards

α−β and β−γ phase boundaries of solid oxygen observed by adiabatic magnetocaloric effect

Thermal hysteresis of the dielectric susceptibility of solid oxygen in the audio frequency range

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