The specific heat of solid oxygen

Fagerstroem, C. H.; Hallett, A. C. Hollis

doi:10.1007/bf00628329

Cited by 48 publications

(30 citation statements)

References 7 publications

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“…Though none of the measured thermodynamic characteristics as well as the molar volume [5] show any jump at the a-fi transition point and, moreover, the heat of transition has not been detected in precise calorimetric study [3], the a-p transformation is beyond all doubts a first order phase transition. This conclusion follows, for instance, from the observation of hysteresis of the magnetization curves at the transition [11].…”

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Thermal conductivity of solid oxygen

et al. 1993

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This paper reports the results of the first measurements of the thermal conductivity of the a, )3, and y phases of solid oxygen over the temperature range of 1-52 K. A simple qualitative analysis was performed to explain the observed anomalies in thermal conductivity, which manifested themselves by a jump at the a-fi transition, the anomalously weak temperature dependence in the p phase, and an increase of the conductivity with temperature in the y phase.PACS numbers: 66.70.+f, 31.70.Ks, 75.20.Ck, Solid oxygen, a unique crystal combining properties of a molecular crystal and a magnet, has been a subject of intensive experimental and theoretical studies during the last two decades (see, for example [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17], and references therein). The following picture has emerged as a result of those studies. Oxygen exists under the equilibrium vapor pressure in three crystalline modifications. The orientationally ordered monoclinic low temperature a phase (C2/m) is a collinear two-sublattice quasi-2D antiferromagnet. The phase transition (7^ = 23.9 K) into the intermediate rhombohedral /3 phase (R3m) is associated with the transformation of the magnetic structure. The nature of this transformation is still a subject for discussion [13].Though none of the measured thermodynamic characteristics as well as the molar volume [5] show any jump at the a-fi transition point and, moreover, the heat of transition has not been detected in precise calorimetric study [3], the a-p transformation is beyond all doubts a first order phase transition. This conclusion follows, for instance, from the observation of hysteresis of the magnetization curves at the transition [11].The long-range magnetic order in /3-oxygen is most probably absent; however the short-range order with the correlation length of 5 A in three-sublattice or incommensurate helicoidal structures persists over the whole range of the existence of the phase [ 11,14,15].Both the low temperature phases have the same orientational structure in which the molecular axes are collinear and perpendicular to the close packed layers. The spectrum of elementary excitations in the a phase consists of (besides acoustic modes) two libron modes at 43 and 78 cm -1 [2] and two magnon ones at 6.4 and 27 cm -1 [1,4]. No magnon excitations were found in the p phase and there is one twofold degenerated libron mode at 50 cm" 1 [2].The p-y transition (7^=43.8 K) is accompanied by a radical rearrangement of the lattice, a considerable jump (5.4%) of volume [5], and high value of the latent heat of the transition [3]. The y phase has an eight-molecule cubic cell with an orientationally disordered structure with Pm3n symmetry. It exhibits paramagnetic properties with a quasi-ID magnetic short-range order [9,10].In this paper we report results of the first measurements of the thermal conductivity of the a, /?, and y phases of solid oxygen.The measurements of the thermal conductivity were carried out by the stationary heat flux method over a temperature ran...

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Thermal conductivity of solid oxygen

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“…3(b). 35 This is more than twice the value estimated from the magnetization curve. This discrepancy cannot be explained by the slight difference in the experimental conditions: B Max = 137 T in the temperature measurement, and B Max = 130 T in the magnetization curve.…”

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Irreversible Heating Measurement with Microsecond Pulse Magnet: Example of the α–θ Phase Transition of Solid Oxygen

et al. 2016

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Dissipation inevitably occurs in first-order phase transitions, leading to irreversible heating. Conversely, the irreversible heating effect may indicate the occurrence of the first-order phase transition. We measured the temperature change at the magnetic-field-induced α-θ phase transition of solid oxygen. A significant temperature increase from 13 to 37 K, amounting to 700 J/mol, due to irreversible heating was observed at the first-order phase transition. We argue that the hysteresis loss of the magnetization curve and the dissipative structural transformation account for the irreversible heating. The measurement of irreversible heating can be utilized to detect the first-order phase transition in combination with an ultrahigh magnetic fields generated in a time of µs order.

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“…According to the studies of thermal capacity [24,25], under equilibrium vapor pressure two phase transitions are observed in solid O 2 at temperatures Т ab = 23,88 К and Т bg = 43,78 К. Temperature Т tr = 54,36 К is a triple point of solid O 2 .…”

Section: Phase Transitions In Solid Oxygen and Discussionmentioning

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Low-frequency internal friction as express-method for identification of cryocrystals in pores of the solids

et al. 2016

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Abstract.We show that studying of low-frequency internal friction (LFIF) of solid samples at low temperatures allows determining the presence of various gases absorbed, for some reasons, in pores and caverns of the solids. The gases come over to a solid state (cryocrystals) and exist in the pores under corresponding thermodynamic conditions giving an additional contribution to the LFIF spectra. The spectra reflect the special points of the gases (temperatures of melting or phase transitions). This information gives a real opportunity for identification of gas in the matrix, i.e. the studied solids. This may be of great importance for investigations of cosmic or geological samples, for instance, asteroids, meteorites, rock formations, etc. The LFIF method allows identification of gas media surrounding the studied sample.Introduction.

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The specific heat of solid oxygen

Cited by 48 publications

References 7 publications

Thermal conductivity of solid oxygen

Thermal conductivity of solid oxygen

Irreversible Heating Measurement with Microsecond Pulse Magnet: Example of the α–θ Phase Transition of Solid Oxygen

Low-frequency internal friction as express-method for identification of cryocrystals in pores of the solids

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