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Optical spectra and relaxation of Eu+3 in germanate glasses
Vol. 12, No. 4
ABSTRACTS OF ARTICLES TO APPEAR IN J. PHYS. CHEM. SOLIDS
Electron transfer to the transition metals quenches their moments so that they become nonmagnetic at high Al concentrations. The peculiarities in the mechanism of magnetization which appear rn rare earth dialuminides when Al is replaced by a transition metal have been studied in detail at cryogenic temperatures. The first replacement of Al results in a decrease
9.
in
saturation moment. Neutron diffraction verifies the low ordered rare earth sublattice moments and reveals the ‘lost part’ as a disordered component. Considerable magnetic hardness develops in certain regions of concentration often connected with spontaneous increases in magnetization with field. All available evidence suggests the presence of unusual domain wall effects to be responsible for this effect. High remanences develop in both the hexagonal and in the cubic structures in the intermediate region. The development of disordered magnetic components is connected either with the disorder on crystallographic sites or changes in the free electron concentration.
OPTICAL SPECTRA AND RELAXATION OF 3in GERMANATE GLASSES Eu~ R. Reisfeld and N. Lieblich, Department of Inorganic and Analytical Chemistry, The Hebrew University.
3 Optical absorption andasemission spectra of Eu~ in germanate glass, as well the fluorescence decay time of 5D 0 -÷ t ‘F1 were measured. Oscillator strengths up to ~60nm were calculated 3in various glasses. It and was compared found that with those of Eu~ the hypersensitive transitions ‘F 5D 5D 0 -÷ 2 and 0 ‘F2 were stronger in germanate than in silicate or phosphate glasses, owing to covalency 5D effects. Transition rates and efficiencies from 0 to the ground levels and 5D 5D 1 0 were calculated. Fluorescence was observed 5D 5D 5L from the 2, 3, 6 levels in addition to that from 5D 5D 0 and 1 observed in phosphate and silicate glasses. The appearence of fluorescence from the higher levels is attributed to the influence of the lower phonon energy of germanate glasses. —~
-~
Received 11 September 1972 Revised 2 November 1972
CHAMPS HYPERFINS ET MODELE SEMIMICROSCOPIQUE NON-LOCAL DE L’INVAR H. Rechenberg, L. Billard, A. Chamberod et M. Natta, Centre d’Etudes Nucléaires de Grenoble, Physique du Solide, 38-Grenoble, France.
The analysis of MOssbauer spectrum obtained on Feo.6aNio.32 bulk samples shows the presence of a 50kG peak separated from the high field peak. This fact is interpreted with a model which is derived from the Kachi and Asano one by taking into account the non-local interaction between cells of 12 atoms. l’h.is model, which explains the 50kG peak together with the variation of the magnetization with concentration confirms the Shimizu and Hirooka hypothesis of a first order transition near 30% of nickel. Received 27 July 1972
10
Received 21 June 1972 Revised 2 November 1972
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SOLID SOLUTION FORMATION IN THE SYSTEMS CUMmX2 _AgMinX2 WHERE Mm = Al, Ga, In ANDX2 = S, Se M. Robbins, J.C. Phillips, and V.G. Lambrecht, Jr., Bell Laboratories, Murray Hill, New Jersey 07974. A study of solid solution formation in the
systems CuAIX 2 —AgAIX2, CuGaX2 —AgGaX2 and CuI~2—Agl~2,where X = 11X S, Se, has shown that when M” = Al and Ga, CuM’ 2 and AgMinX2 were nothowever, completely miscible. The CuInX2 —AgInX2 system, showed complete solid solubiity. The limits of solid solubility are explained in terms of the c/a ratio and the internal atomic coordinate u. The lattice is a linear function of composition, whileconstant c bows aupwards. This behavior is also discussed in terms of trends in 2 c/a. Received 22 August 1972 —
II.
IODINE AS A DONOR IN CdS H.R. Vydyanath, S.S. Chern and F.A. Kroger, Department of Materials Science, University of Southern California, University Park, Los Angeles, California 90007.
Iodine doped single crystals of CdS were grown from the vapor phase. High temperature Hall effect
ABSTRACTS OF ARTICLES TO APPEAR IN J. PHYS. CHEM. SOLIDS
Electron transfer to the transition metals quenches their moments so that they become nonmagnetic at high Al concentrations. The peculiarities in the mechanism of magnetization which appear rn rare earth dialuminides when Al is replaced by a transition metal have been studied in detail at cryogenic temperatures. The first replacement of Al results in a decrease
9.
in
saturation moment. Neutron diffraction verifies the low ordered rare earth sublattice moments and reveals the ‘lost part’ as a disordered component. Considerable magnetic hardness develops in certain regions of concentration often connected with spontaneous increases in magnetization with field. All available evidence suggests the presence of unusual domain wall effects to be responsible for this effect. High remanences develop in both the hexagonal and in the cubic structures in the intermediate region. The development of disordered magnetic components is connected either with the disorder on crystallographic sites or changes in the free electron concentration.
OPTICAL SPECTRA AND RELAXATION OF 3in GERMANATE GLASSES Eu~ R. Reisfeld and N. Lieblich, Department of Inorganic and Analytical Chemistry, The Hebrew University.
3 Optical absorption andasemission spectra of Eu~ in germanate glass, as well the fluorescence decay time of 5D 0 -÷ t ‘F1 were measured. Oscillator strengths up to ~60nm were calculated 3in various glasses. It and was compared found that with those of Eu~ the hypersensitive transitions ‘F 5D 5D 0 -÷ 2 and 0 ‘F2 were stronger in germanate than in silicate or phosphate glasses, owing to covalency 5D effects. Transition rates and efficiencies from 0 to the ground levels and 5D 5D 1 0 were calculated. Fluorescence was observed 5D 5D 5L from the 2, 3, 6 levels in addition to that from 5D 5D 0 and 1 observed in phosphate and silicate glasses. The appearence of fluorescence from the higher levels is attributed to the influence of the lower phonon energy of germanate glasses. —~
-~
Received 11 September 1972 Revised 2 November 1972
CHAMPS HYPERFINS ET MODELE SEMIMICROSCOPIQUE NON-LOCAL DE L’INVAR H. Rechenberg, L. Billard, A. Chamberod et M. Natta, Centre d’Etudes Nucléaires de Grenoble, Physique du Solide, 38-Grenoble, France.
The analysis of MOssbauer spectrum obtained on Feo.6aNio.32 bulk samples shows the presence of a 50kG peak separated from the high field peak. This fact is interpreted with a model which is derived from the Kachi and Asano one by taking into account the non-local interaction between cells of 12 atoms. l’h.is model, which explains the 50kG peak together with the variation of the magnetization with concentration confirms the Shimizu and Hirooka hypothesis of a first order transition near 30% of nickel. Received 27 July 1972
10
Received 21 June 1972 Revised 2 November 1972
8.
vii
SOLID SOLUTION FORMATION IN THE SYSTEMS CUMmX2 _AgMinX2 WHERE Mm = Al, Ga, In ANDX2 = S, Se M. Robbins, J.C. Phillips, and V.G. Lambrecht, Jr., Bell Laboratories, Murray Hill, New Jersey 07974. A study of solid solution formation in the
systems CuAIX 2 —AgAIX2, CuGaX2 —AgGaX2 and CuI~2—Agl~2,where X = 11X S, Se, has shown that when M” = Al and Ga, CuM’ 2 and AgMinX2 were nothowever, completely miscible. The CuInX2 —AgInX2 system, showed complete solid solubiity. The limits of solid solubility are explained in terms of the c/a ratio and the internal atomic coordinate u. The lattice is a linear function of composition, whileconstant c bows aupwards. This behavior is also discussed in terms of trends in 2 c/a. Received 22 August 1972 —
II.
IODINE AS A DONOR IN CdS H.R. Vydyanath, S.S. Chern and F.A. Kroger, Department of Materials Science, University of Southern California, University Park, Los Angeles, California 90007.
Iodine doped single crystals of CdS were grown from the vapor phase. High temperature Hall effect