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Distribution of hydroxide ions in doped alkali halide crystals
ABSTRACTS OF PAPERS TO APPEAR IN model between octahedral sites can be drawn from experiments at small and large scattering
12.
G. Buisson, Centre d’etudes Nucleaires, Cedex 85, 38-Grenoble-Gare, France The compounds ATiTO5 are isomorphous with HoMn2O5 when the rare earth ionic radius is intermediate between that of Gd and Pr. Pyrochiore (T2Ti2O7) and perowskite (ATO3) structures are found simultaneously. A purpose of this study investigate the distribution 3~and Tiwas ~ intoATiTO of A 5 over the two different available sites having an octahedral and square pyramid oxygen environment. A neutron diffraction 3~ study of Ndof compounds has shown that95Aper cent occupation the octahedral site was and 57 per cent when A3~is Cr~ and Fe3~ respectively. This is easily interpreted using crystal field theory.
Vol.7, No.23
Recetved 15 July 1969
Received 25 September 1969 Revised 13 October 1969
ETUDE PAR RAYONS X ET NEUTRONS DE LA SERIE ISOMORPHE ATiTO ~• A = Cr, Mn, Fe. T = TERRES RARES
PHYS. CHEM. SOLIDS
No magnetic ordering was observed for MnT1NdO 5.
vectors. An anomaly has been observed in the line width for large scattering vectors as well as in the Debye—Waller factor at temperatures close to the critical temperature.
11.
J.
DISTRIBUTION OF HYDROXIDE IONS IN DOPED ALKALI HALIDE CRYSTALS Thomas G. Stoebe, Division of Metallurgical Engineering, University of Washington, Seattle, Washington 98105
The available information concerning the distribution of hydroxide ions in alkali halide crystals is reviewed. The various possible reactions among the hydroxide ions and divalent cation impurities and their accompanying charge compensating cation vacancies are given and discussed in terms of the available ionic conductivity and optical absorption data. The possible hydroxide ion complexes are discussed in terms of ESR results. Complexes containing hydroxide ions, each on their own anion site, with cation impurities and vacancies on adjacent sites are indicated as being the most probable to occur. Different geometries of such a complex are discussed in terms of the available experimental data.
Received 25 August 1969
In CrTiNdO 5 both Cr and Ndlie spins become 3~spins in the XY ordered below 13°KNd plane (+Gx—Ay). Cr3~ions in octahedral sites (95 per cent) have spins along the z axis (+ Az) while the remaining Cr ~ ions square pyramid sites (5 per cent) have spins in the XY plane (+ Ay). Shubnikov group is Pbam~ In FeTiNdO 3~spins are not ordered 5, Ndlie in XY plane with a CxFy at 1.5°K Fe3~spins configuration for both sites. Shubnikov group is P 2~b’am’. For these two compounds the spin direction in the XY plane makes an angle of approximately 12°with the Y axis. In CrTiNdO5 the spin direction can be explained only by assuming anisotropic exchange.
13.
ETUDE PAR RESONANCE ELECTRONIQUE DU TRITIUM ATOMIQUE FORME AU SEIN DE CRISTAUX DE FLUORURE DE LITHIUM IRRADIE AUX NEUTRONS Maria T. Causa, Denis Raoux et Christiane Taupin, Laboratoire de Physique des Solides, Faculté des Sciences, 91 Orsay, France
An EPR investigation of neutron irradiated LiF single crystals shows that atomic Tritium may be found in several sitesit ofis the of them has been identified: the lattice. 1/4, 1/4One 1/4 interstitial site. Quantitative interpretation of this EPR spectrum needs the relaxation of the lattice. The nearest neighbour ions have to be
12.
G. Buisson, Centre d’etudes Nucleaires, Cedex 85, 38-Grenoble-Gare, France The compounds ATiTO5 are isomorphous with HoMn2O5 when the rare earth ionic radius is intermediate between that of Gd and Pr. Pyrochiore (T2Ti2O7) and perowskite (ATO3) structures are found simultaneously. A purpose of this study investigate the distribution 3~and Tiwas ~ intoATiTO of A 5 over the two different available sites having an octahedral and square pyramid oxygen environment. A neutron diffraction 3~ study of Ndof compounds has shown that95Aper cent occupation the octahedral site was and 57 per cent when A3~is Cr~ and Fe3~ respectively. This is easily interpreted using crystal field theory.
Vol.7, No.23
Recetved 15 July 1969
Received 25 September 1969 Revised 13 October 1969
ETUDE PAR RAYONS X ET NEUTRONS DE LA SERIE ISOMORPHE ATiTO ~• A = Cr, Mn, Fe. T = TERRES RARES
PHYS. CHEM. SOLIDS
No magnetic ordering was observed for MnT1NdO 5.
vectors. An anomaly has been observed in the line width for large scattering vectors as well as in the Debye—Waller factor at temperatures close to the critical temperature.
11.
J.
DISTRIBUTION OF HYDROXIDE IONS IN DOPED ALKALI HALIDE CRYSTALS Thomas G. Stoebe, Division of Metallurgical Engineering, University of Washington, Seattle, Washington 98105
The available information concerning the distribution of hydroxide ions in alkali halide crystals is reviewed. The various possible reactions among the hydroxide ions and divalent cation impurities and their accompanying charge compensating cation vacancies are given and discussed in terms of the available ionic conductivity and optical absorption data. The possible hydroxide ion complexes are discussed in terms of ESR results. Complexes containing hydroxide ions, each on their own anion site, with cation impurities and vacancies on adjacent sites are indicated as being the most probable to occur. Different geometries of such a complex are discussed in terms of the available experimental data.
Received 25 August 1969
In CrTiNdO 5 both Cr and Ndlie spins become 3~spins in the XY ordered below 13°KNd plane (+Gx—Ay). Cr3~ions in octahedral sites (95 per cent) have spins along the z axis (+ Az) while the remaining Cr ~ ions square pyramid sites (5 per cent) have spins in the XY plane (+ Ay). Shubnikov group is Pbam~ In FeTiNdO 3~spins are not ordered 5, Ndlie in XY plane with a CxFy at 1.5°K Fe3~spins configuration for both sites. Shubnikov group is P 2~b’am’. For these two compounds the spin direction in the XY plane makes an angle of approximately 12°with the Y axis. In CrTiNdO5 the spin direction can be explained only by assuming anisotropic exchange.
13.
ETUDE PAR RESONANCE ELECTRONIQUE DU TRITIUM ATOMIQUE FORME AU SEIN DE CRISTAUX DE FLUORURE DE LITHIUM IRRADIE AUX NEUTRONS Maria T. Causa, Denis Raoux et Christiane Taupin, Laboratoire de Physique des Solides, Faculté des Sciences, 91 Orsay, France
An EPR investigation of neutron irradiated LiF single crystals shows that atomic Tritium may be found in several sitesit ofis the of them has been identified: the lattice. 1/4, 1/4One 1/4 interstitial site. Quantitative interpretation of this EPR spectrum needs the relaxation of the lattice. The nearest neighbour ions have to be