Two compounds of the type Eu1+xBa2−xCu3O7−δ with x=0.15 and x=0.25 have been prepared and studied by means of 151Eu-Mössbauer spectroscopy, in order to detect phonon anomalies. The spectra consist of a single absorption line at all temperatures. The areas of the absorption lines do not depend on x. This means that we only observe the spectra of the Eu at the rare earth sites. A mean square displacement analysis reveal low temperature anharmonicity. Phonon anomalies are observed below about 90 K, which is the transition temperature of the pure compound (x = 0). Moreover we observe a softening of the lattice with increasing x.
Low temperature anharmonicity and phonon anomalies at 151Eu sites in Eu1+xBa2−xCu3O7−δ / L. Cianchi; F. Del Giallo; F. Pieralli; M. Mancini; S. Sciortino; G. Spina; N. Ammannati; R. Garré. - In: SOLID STATE COMMUNICATIONS. - ISSN 0038-1098. - STAMPA. - 80:(1991), pp. 705-708. [10.1016/0038-1098(91)90892-Y]
Low temperature anharmonicity and phonon anomalies at 151Eu sites in Eu1+xBa2−xCu3O7−δ
SCIORTINO, SILVIO;SPINA, GABRIELE;
1991
Abstract
Two compounds of the type Eu1+xBa2−xCu3O7−δ with x=0.15 and x=0.25 have been prepared and studied by means of 151Eu-Mössbauer spectroscopy, in order to detect phonon anomalies. The spectra consist of a single absorption line at all temperatures. The areas of the absorption lines do not depend on x. This means that we only observe the spectra of the Eu at the rare earth sites. A mean square displacement analysis reveal low temperature anharmonicity. Phonon anomalies are observed below about 90 K, which is the transition temperature of the pure compound (x = 0). Moreover we observe a softening of the lattice with increasing x.
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