Filters
Results 1 - 1 of 1
Results 1 - 1 of 1.
Search took: 0.014 seconds
AbstractAbstract
[en] Since the discovery of high-Tc superconductivity in YBa2Cu3O7 oxides several studies of metal ions substitutions were reported. The observed depression on Tc without a systematic correlation with the charge and magnetic moment of Cu substituents claims for more detailed information about its local properties as can be revealed by 57Fe Moessbauer spectroscopy. The results for different iron concentrations combined with modifications of the superconducting transition are discussed concerning the presence of magnetic moments on the Fe ions and the preferential occupation of Cu(1) sites, recently confirmed by neutron and electron diffraction experiments. The oxygen coordination for the different iron species are proposed on the basis of their dependence on Fe concentration, their behavior at high temperatures as well as the electron diffraction and electron microscopy measurements reported for Fe: YBa2Cu3O7 samples. (author)
[pt]
Desde a descoberta da supercondutividade a altas temperaturas Tc em oxidos de YBa2Cu3O7 varios estudos de substituicoes de ions metalicos relatados. A depressao observada sobre Tc sem uma correlacao sistematica com a carga e o momento magnetico dos substituintes de Cu reclamam por informacoes mais detalhadas sobre suas propriedades locais como pode ser revelado por espectroscopia Moessbauer do 57Fe. Os resultados para diferentes concentracoes de ferro combinados com as modificacoes da transicao supercondutora sao discutidos relativos a presenca de momentos magneticos sobre os ions de Fe e a ocupacao preferencial de sitios de Cu(1), configurados recentementes por experiencias de difracao de neutros e eletrons. Propoe-se a coordenacao do oxigenio para as diferentes especies de ferro em bases da sua dependencia sobre a concentracao de Fe, seu comportamento a altas temperaturas tanto quanto medidas de difracao de eletrons e microscopia de eletrons relatados para amostras de Fe: YBa2Cu3O7. (L.C.)Secondary Subject
Source
1988; 28 p
Record Type
Report
Report Number
Country of publication
ALKALINE EARTH METAL COMPOUNDS, ATOMIC IONS, CHARGED PARTICLES, COHERENT SCATTERING, COPPER COMPOUNDS, DIFFRACTION, ELECTRIC CONDUCTIVITY, ELECTRICAL PROPERTIES, EVEN-ODD NUCLEI, INTERMEDIATE MASS NUCLEI, IONS, IRON ISOTOPES, ISOTOPES, MICROSCOPY, NUCLEI, OXYGEN COMPOUNDS, PHYSICAL PROPERTIES, SCATTERING, STABLE ISOTOPES, TRANSITION ELEMENT COMPOUNDS
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue