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The thermal conductivity of the amorphous alloy Fe40Ni40P14B6 is investigated with the aim to separate out the lattice contribution and to compare it with that of amorphous dielectrics. The problems of the influence of the radiative transfer of heat between the sample and its environment, which causes errors in the determination of thermal conductivity, are discussed. The authors found that the temperature dependence of the lattice thermal conductivity of the alloys is qualitatively the same as that of amorphous dielectrics.

The results of measurements of the thermal conductivity of REIn3 (RE = Pr, Nd, Dy, Ho, Tm) compounds as a function of the temperature in the interval 4–300 K in the absence and in the presence of an external magnetic field of 8 T are presented. Except for PRIn3 all the compounds are antiferromagnetic. YIn3 was also measured as a reference compound. The results were analysed in the paramagnetic phase, where an influence of the crystalline electric field on the thermal conductivity was found. Drastic changes in the thermal conductivity were observed and analysed in the vicinity of the Néel temperature and in the antiferromagnetic phases of the compounds. Below the Néel temperature an additional magnon contribution to the thermal conductivity was separated out.

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Precise magnetotransport studies of heat and charge carriers in polycrystalline MgB 2 show that magnetic fields up to 8 T remarkably influence electrical resistivity, thermoelectric power and thermal conductivity. The superconducting transition temperature shifts from 39 K to 19 K at 8 T as observed on electric signals. The temperature transition width is weakly broadened. Electron and phonon contributions to the thermal conductivity are separated and discussed. The Debye temperature calculated from a phonon drag thermoelectric power component is inconsistent with values derived through other effects.

Thermal conductivity of crystalline natural nitrogen was investigated over the temperature range 1.2 -38 K. The temperature dependence of thermal conductivity of a-nitrogen has been determined in temperatures below 18 K. The thermal conductivity coeScient reaches the maximum value 250 mW/cm K at 3.6 K. The results of the experiment below 14 K can be well described by integral equation obtained by the method of Callaway. Relaxation times for various mechanisms of phonon scattering have been determined. The results of our experiments are in accord with earlier literature data for temperatures above 18 K.

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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