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Force-constant models of lattice vibrations in rare-earth halides
Solid State Communications,
Vol. 8,
pp. i—iv,
1970.
Pergamon Press.
Printed in Great Britain
Abstracts of Articles to be Published in The Journal of Physics and Chemistry of Solids ‘J Phys. Chem. Solids (to be published)’ should be cited in references to material quoted from this section prior to the publication of the relevant article.
1.
FORCE-CONSTANT MODELS OF LATTICE VIBRATIONS IN RARE-EARTH HALIDES G.E. Stedman and D.J. Newman, Department of Physics, Queen Mary College, Mile End Road, London E. 1.,
Various harmonic force models are used to fit experimental k = 0 lattice vibration frequencies in LaCI3, CeC13, PrCI3 and LaBr3. It is shown that a very approximate model using only two parameters gives a reasonable fit to six or more frequencies. This is not greatly improved by the use of more sophisticated models. The k = 0 eigenvector for a particular choice of force constants is also given.
this may to a good approximation be neglected. In particular the spin wave spectrum of the rare earth alloy Tb-Ho is considered, a system in which the angular momenta are coupled by the longe range Rudermann—Kittel interaction, and in which resonant magnon modes have been observed experimentally. A discussion is also given of the likely behaviour of spin waves in other Tb-rare earth alloys. Received 18 March 1969 Revised 20 October 1969
3.
Received 13 October 1969
2.
THEORY OF IMPURITY STATES IN SYSTEMS WITH LONG RANGE INTERACTIONS SPIN WAVES IN Tb-Ho ALLOYS J.A. Blackman, Department of Theoretical Physics, Oxford University, England, and Department of Physics, Atomic Energy Establishment Risö, Roskilde, Denmark —
The theoretical treatment of impurity problems is generally restricted to cases involving interactions of short range. We present here a discussion of the long range case and show how certain of the impurity terms may be treated exactly. One term remains intractable, however, but it is shown that, under some circumstances,
EPR-SPECTRA OF SODIUM-TITANIUMSILICATE GLASSES AND OF TITANIUMCONTAINING OXIDE COMPOUNDS H. Böhm and G. Bayer, Institut für Kristallographie und Petrographie, Eidg. Techn. Hochschule, Zurich, Switzerland
The formation of trivalent titanium in glasses and its dependence on chemical composition, temperature, atmosphere and irradiation were studied by means of EPR. For comparison and assignment of the resonances several crystalline titanium-containing oxide compounds were also investigated after slight reduction at 600°Cin hydrogen. Received 14 August 1969
4.
NUCLEAR MAGNETIC RESONANCE STUDY OF SEMICONDUCTING VANADIUM PHOSPHATE GLASS
Vol. 8,
pp. i—iv,
1970.
Pergamon Press.
Printed in Great Britain
Abstracts of Articles to be Published in The Journal of Physics and Chemistry of Solids ‘J Phys. Chem. Solids (to be published)’ should be cited in references to material quoted from this section prior to the publication of the relevant article.
1.
FORCE-CONSTANT MODELS OF LATTICE VIBRATIONS IN RARE-EARTH HALIDES G.E. Stedman and D.J. Newman, Department of Physics, Queen Mary College, Mile End Road, London E. 1.,
Various harmonic force models are used to fit experimental k = 0 lattice vibration frequencies in LaCI3, CeC13, PrCI3 and LaBr3. It is shown that a very approximate model using only two parameters gives a reasonable fit to six or more frequencies. This is not greatly improved by the use of more sophisticated models. The k = 0 eigenvector for a particular choice of force constants is also given.
this may to a good approximation be neglected. In particular the spin wave spectrum of the rare earth alloy Tb-Ho is considered, a system in which the angular momenta are coupled by the longe range Rudermann—Kittel interaction, and in which resonant magnon modes have been observed experimentally. A discussion is also given of the likely behaviour of spin waves in other Tb-rare earth alloys. Received 18 March 1969 Revised 20 October 1969
3.
Received 13 October 1969
2.
THEORY OF IMPURITY STATES IN SYSTEMS WITH LONG RANGE INTERACTIONS SPIN WAVES IN Tb-Ho ALLOYS J.A. Blackman, Department of Theoretical Physics, Oxford University, England, and Department of Physics, Atomic Energy Establishment Risö, Roskilde, Denmark —
The theoretical treatment of impurity problems is generally restricted to cases involving interactions of short range. We present here a discussion of the long range case and show how certain of the impurity terms may be treated exactly. One term remains intractable, however, but it is shown that, under some circumstances,
EPR-SPECTRA OF SODIUM-TITANIUMSILICATE GLASSES AND OF TITANIUMCONTAINING OXIDE COMPOUNDS H. Böhm and G. Bayer, Institut für Kristallographie und Petrographie, Eidg. Techn. Hochschule, Zurich, Switzerland
The formation of trivalent titanium in glasses and its dependence on chemical composition, temperature, atmosphere and irradiation were studied by means of EPR. For comparison and assignment of the resonances several crystalline titanium-containing oxide compounds were also investigated after slight reduction at 600°Cin hydrogen. Received 14 August 1969
4.
NUCLEAR MAGNETIC RESONANCE STUDY OF SEMICONDUCTING VANADIUM PHOSPHATE GLASS