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Electrical properties of some nickel-group chalcogenides
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Vlll
ABSTRACTS
OF PAPERS TO APPEAR
10. ELECTRICAL PROPERTIES OF SOME NICKEL-GROUP CHALCOGENIDES. F. Hulliger (Cyanimid European Research Institute, Cologny-Geneva, Switzerland). The conditions for non-metallic conduction in transition-element compounds are discussed and used to interpret the electrical properties of the nickel-group chalcogenides. The energy gaps of the semiconducting representatives were derived either from resistivity or from diffuse-reflectance measurements. The lattice constants of NiSeTe, PdSSe, PdSeTe, and PtSeTe are reported. (Received 25 June 1964) (Revised 28 September 1964) 11. THE SPECIFIC HEAT OF COPPER, NICKEL, AND COPPER-NICKEL ALLOYS. * R. E. Pawel and E. E. Stansbury (Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, and Department of Chemical and Metallurgical Engineering, University of Tennessee, Knoxville, Tennessee, U. S. A. ). The specific heat of high-purity copper, nickel, and several nickel-rich alloys from room temperature to 6000C is reported. The data, obtained with an adiabatic calorimeter, were reproducible to within 2 0.25 per cent and have an estimated absolute error of less than f 0.5 per cent. (Received 30 September 1964) 12. MAGNETIC STRUCTURE OF CaMnSiO4.0 L. G. Caron, R. P. Santoro and R. E. Newnham (Electrical Engineering Department, Massachusetts Institute of Technology, Cambridge, Massachusetts, U.S. A. ). CaMnSiO4 crystallizes in the olivine structure and is antiferromagnetic below 9OK; magnetic-susceptibility measurements gave 6 = 260K and peff = 5. 77 clg. The cation distribution and magnetic structure were established by neut*Research sponsored by the U.S.A.E.C. under contract with the Dept. of Chemical & Metallurgical Engineering, University of Tennessee. §Supported by the U.S. A. F., Aeronautical Systems Division, under Contract AF 33(616)-8353, and by Advanced Research Projects Agency, Department of Defense, through Contract SD90.
IN J. PHYS. CHEM. SOLIDS
Vol. 2, No. 12
ron diffraction. Divalent manganese occupies the inversion centers with calcium in mirror plane positions, isostructural with CaMgSiO4. At low temperatures the Mn moments align in antiferromagnetic chains along b with spin directions collinear to c. (Received
5 October
1964)
13. PHASE EQUILIBRIA IN THE GaAs AND‘THE GaP SYSTEMS. C. D. Thurmond (Bell Telephone Laboratories, Inc., Murray Hill, New Jersey, U. S. A. ). A thermodynamically consistent treatment of the available solubility and vapor pressure measurements for the two binary systems GaAs GaP has been made leading to reasonable estimates of the complete composition-temperature and vapor pressure-temperature curves. It has been found that (a) the decomposition pressure of Gap is essentially the same as that of GaAs in the temperature region where the equilibrium phases are nearly pure gallium; (b) that GaAs should evaporate congruently at temperatures up to about 660°C and GaP up to temperatures of about 680°C; (c) that both positive and negative departures from ideality occur along the liquidus curves; (d) that the negative departures from ideality that occur in dilute solutions at low temperatures along the liquidus curves arise, principally, from an entropy effect which is in consistent with the formation of associated complexes previously postulated; (e) that the value of the heat of formation at 2980K of GaAs is -17.7 * 1 kcal and of GaP is -24.4 f 1.25 kcal. (Received
5 October
1964)
14. ON THE MAGNETIC AND CHEMICAL PROPERTIES OF EUROPIUM FLUORIDE. * K. Lee and H. Muir (Varian Associates, Palo Alto, California, U. S. A. ) and E. Catalan0 (University of California, Lawrence Radiation Laboratory, Live rmore, California, U. S. A. ). Electron spin resonance, chemical, and X-ray studies have been carried out on several different, nominally EuF2, single crystal samples. EuF2 has been reported to be apparently antiferromagnetic. This study has shown the various samples to be paramagnetic down to 1.6OK. In some samples, however, magnetically *This work, in part, was performed auspices of the U.S. A. E. C.
under the
Vlll
ABSTRACTS
OF PAPERS TO APPEAR
10. ELECTRICAL PROPERTIES OF SOME NICKEL-GROUP CHALCOGENIDES. F. Hulliger (Cyanimid European Research Institute, Cologny-Geneva, Switzerland). The conditions for non-metallic conduction in transition-element compounds are discussed and used to interpret the electrical properties of the nickel-group chalcogenides. The energy gaps of the semiconducting representatives were derived either from resistivity or from diffuse-reflectance measurements. The lattice constants of NiSeTe, PdSSe, PdSeTe, and PtSeTe are reported. (Received 25 June 1964) (Revised 28 September 1964) 11. THE SPECIFIC HEAT OF COPPER, NICKEL, AND COPPER-NICKEL ALLOYS. * R. E. Pawel and E. E. Stansbury (Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, and Department of Chemical and Metallurgical Engineering, University of Tennessee, Knoxville, Tennessee, U. S. A. ). The specific heat of high-purity copper, nickel, and several nickel-rich alloys from room temperature to 6000C is reported. The data, obtained with an adiabatic calorimeter, were reproducible to within 2 0.25 per cent and have an estimated absolute error of less than f 0.5 per cent. (Received 30 September 1964) 12. MAGNETIC STRUCTURE OF CaMnSiO4.0 L. G. Caron, R. P. Santoro and R. E. Newnham (Electrical Engineering Department, Massachusetts Institute of Technology, Cambridge, Massachusetts, U.S. A. ). CaMnSiO4 crystallizes in the olivine structure and is antiferromagnetic below 9OK; magnetic-susceptibility measurements gave 6 = 260K and peff = 5. 77 clg. The cation distribution and magnetic structure were established by neut*Research sponsored by the U.S.A.E.C. under contract with the Dept. of Chemical & Metallurgical Engineering, University of Tennessee. §Supported by the U.S. A. F., Aeronautical Systems Division, under Contract AF 33(616)-8353, and by Advanced Research Projects Agency, Department of Defense, through Contract SD90.
IN J. PHYS. CHEM. SOLIDS
Vol. 2, No. 12
ron diffraction. Divalent manganese occupies the inversion centers with calcium in mirror plane positions, isostructural with CaMgSiO4. At low temperatures the Mn moments align in antiferromagnetic chains along b with spin directions collinear to c. (Received
5 October
1964)
13. PHASE EQUILIBRIA IN THE GaAs AND‘THE GaP SYSTEMS. C. D. Thurmond (Bell Telephone Laboratories, Inc., Murray Hill, New Jersey, U. S. A. ). A thermodynamically consistent treatment of the available solubility and vapor pressure measurements for the two binary systems GaAs GaP has been made leading to reasonable estimates of the complete composition-temperature and vapor pressure-temperature curves. It has been found that (a) the decomposition pressure of Gap is essentially the same as that of GaAs in the temperature region where the equilibrium phases are nearly pure gallium; (b) that GaAs should evaporate congruently at temperatures up to about 660°C and GaP up to temperatures of about 680°C; (c) that both positive and negative departures from ideality occur along the liquidus curves; (d) that the negative departures from ideality that occur in dilute solutions at low temperatures along the liquidus curves arise, principally, from an entropy effect which is in consistent with the formation of associated complexes previously postulated; (e) that the value of the heat of formation at 2980K of GaAs is -17.7 * 1 kcal and of GaP is -24.4 f 1.25 kcal. (Received
5 October
1964)
14. ON THE MAGNETIC AND CHEMICAL PROPERTIES OF EUROPIUM FLUORIDE. * K. Lee and H. Muir (Varian Associates, Palo Alto, California, U. S. A. ) and E. Catalan0 (University of California, Lawrence Radiation Laboratory, Live rmore, California, U. S. A. ). Electron spin resonance, chemical, and X-ray studies have been carried out on several different, nominally EuF2, single crystal samples. EuF2 has been reported to be apparently antiferromagnetic. This study has shown the various samples to be paramagnetic down to 1.6OK. In some samples, however, magnetically *This work, in part, was performed auspices of the U.S. A. E. C.
under the