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Critical behaviour of the two-dimensional Ising antiferromagnets K2 CoF4 and Rb2 CoF4
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ABSTRACTS OF PAPERS TO APPEAR IN J. PHYS. CHEM. SOUDS
High field magnetoresistance measurements have been made on samples of AuPb2 which consist of islands of oriented AuPb2 surrounded by eutectic mixture. The results obtained are very similar to what would be expected for single crystal samples. Open orbits are observed in (100), (110>, (101>, (112> and (211> and [0011 directions. The results are consistent with predictions of the Nearly Free Electron Model. Received 20 July 1973
18.
CALCULATION OF DISTRIBUTION COEFFICIENTS OF DONORS IN Ill—V SEMICONDUCTORS G.B. Stnngfellow, Hewlett-Packard Laboratories, 1501 Page Mill Road, Palo Alto, Ca 94304, U.S.A.
The techniques recently developed for the calculation of Ill—V ternary phase diagrams have been extended to the calculation of distribution coefficients of impurities in Ill—V semiconductors. The distribution coefficients are calculated with no adjustable parameters, the calculation requiring only the temperatures and entropies of fusion, binary phase diagrams and lattice parameters of the relevant 111—V compounds, and the tetrahedral covalent radii, electronegativities, molar volumes and atomization energies of the donor impurities and group III and V elements concerned, The calculation is carried out for common donors 5, Se, Te and Sn at the melting points of the Ill—V compounds GaP, GaAs, GaSb, InP, InAs and InSb, and the results compared with experimental results where available. In GaAs and GaP, the distribution coefficients are calculated versus temperature for solidification from the group III rich melt.
Academy, Annapolis, Maryland 21402, U.S.A. Carl Andeen and Donald Schuele, Case Western Reserve University, Cleveland, Ohio 44106, U.S.A.
The 1000 Hz, 300°Kdielectric constant of two samples of Servofrax arsenic trisulfide glass was measured to an accuracy of about 0.0 1% by the method of substitution (two-fluid technique). The values were determined to be 7.9093 and 7.9097. These results are discussed in the light of recent refractive index and reflectivity measurements. Received 24 September 1973 20.
19.
THE LOW FREQUENCY DIELECTRIC CONSTANT OF VITREOUS ARSENIC TRISULFIDE John Fontaneila, United States Naval
CRITICAL BEHAVIOUR OF THE TWODIMENSIONAL ISING ANTIFERROMAGNETS K2 CoF4 AND Rb2 CoF4 Emil J. Samuelsen, Institutt for Atomenergi, P.O. Box 40, 2007 Kjeller, Norway.
The studies have been performed by means of neutron scattering. We report here the first experimental verification of the theoretical predictions concerning temperature dependence of the long range order parameter of two-dimensional Ising systems, giving the values B = 1.16 ±0.03 and (3 = 0.119 ±0.008 for the critical parameters. Also the parameters for the inverse correlation length and the staggered susceptibility were determined, with exponents v = 0.89 ±0.1 and ~y= 1.34 ±0.22. It was discovered that frozen-in states of stacking of the two-dimensional planes appeared upon quick cooling through the ordering temperature. Received 2 July 1973 Revised 20 September 1973
21. Received 16 July 1973
Vol. 14, No.5
THE HEAT CAPACITIES OF THE NICKEL HEXAMMINE HALIDES S.J. Smith, J.G. Bunting and H. Steeple, The Physics Department, University of Manchester, Institute of Science and Technology, Manchester, England.
ABSTRACTS OF PAPERS TO APPEAR IN J. PHYS. CHEM. SOUDS
High field magnetoresistance measurements have been made on samples of AuPb2 which consist of islands of oriented AuPb2 surrounded by eutectic mixture. The results obtained are very similar to what would be expected for single crystal samples. Open orbits are observed in (100), (110>, (101>, (112> and (211> and [0011 directions. The results are consistent with predictions of the Nearly Free Electron Model. Received 20 July 1973
18.
CALCULATION OF DISTRIBUTION COEFFICIENTS OF DONORS IN Ill—V SEMICONDUCTORS G.B. Stnngfellow, Hewlett-Packard Laboratories, 1501 Page Mill Road, Palo Alto, Ca 94304, U.S.A.
The techniques recently developed for the calculation of Ill—V ternary phase diagrams have been extended to the calculation of distribution coefficients of impurities in Ill—V semiconductors. The distribution coefficients are calculated with no adjustable parameters, the calculation requiring only the temperatures and entropies of fusion, binary phase diagrams and lattice parameters of the relevant 111—V compounds, and the tetrahedral covalent radii, electronegativities, molar volumes and atomization energies of the donor impurities and group III and V elements concerned, The calculation is carried out for common donors 5, Se, Te and Sn at the melting points of the Ill—V compounds GaP, GaAs, GaSb, InP, InAs and InSb, and the results compared with experimental results where available. In GaAs and GaP, the distribution coefficients are calculated versus temperature for solidification from the group III rich melt.
Academy, Annapolis, Maryland 21402, U.S.A. Carl Andeen and Donald Schuele, Case Western Reserve University, Cleveland, Ohio 44106, U.S.A.
The 1000 Hz, 300°Kdielectric constant of two samples of Servofrax arsenic trisulfide glass was measured to an accuracy of about 0.0 1% by the method of substitution (two-fluid technique). The values were determined to be 7.9093 and 7.9097. These results are discussed in the light of recent refractive index and reflectivity measurements. Received 24 September 1973 20.
19.
THE LOW FREQUENCY DIELECTRIC CONSTANT OF VITREOUS ARSENIC TRISULFIDE John Fontaneila, United States Naval
CRITICAL BEHAVIOUR OF THE TWODIMENSIONAL ISING ANTIFERROMAGNETS K2 CoF4 AND Rb2 CoF4 Emil J. Samuelsen, Institutt for Atomenergi, P.O. Box 40, 2007 Kjeller, Norway.
The studies have been performed by means of neutron scattering. We report here the first experimental verification of the theoretical predictions concerning temperature dependence of the long range order parameter of two-dimensional Ising systems, giving the values B = 1.16 ±0.03 and (3 = 0.119 ±0.008 for the critical parameters. Also the parameters for the inverse correlation length and the staggered susceptibility were determined, with exponents v = 0.89 ±0.1 and ~y= 1.34 ±0.22. It was discovered that frozen-in states of stacking of the two-dimensional planes appeared upon quick cooling through the ordering temperature. Received 2 July 1973 Revised 20 September 1973
21. Received 16 July 1973
Vol. 14, No.5
THE HEAT CAPACITIES OF THE NICKEL HEXAMMINE HALIDES S.J. Smith, J.G. Bunting and H. Steeple, The Physics Department, University of Manchester, Institute of Science and Technology, Manchester, England.