Hydrostatic-pressure-induced phase separation in the YBa2Cu4O8 superconductorстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:A micro-Raman study under high hydrostatic pressure (up to similar to 7.5 GPa) has been carried out on YBa2Cu4O8 superconducting single crystals at room and low temperatures down to 77 K. Seven strong modes of A(g) symmetry, two of weak B-2g and B-3g symmetry, and another mode at similar to 431 cm(-1) have been investigated. With increasing hydrostatic pressure the first nine phonons shift to higher energies while the latter is independent of pressure. A splitting of the mode attributed to the in-phase vibrations of the plane O oxygen atoms has been observed. Besides, anomalous nonlinear pressure behavior has been observed for the other A(g) phonons, which is correlated with the splitting of the in-phase mode and the pressure dependence of the superconducting transition temperature of this compound. The results indicate a pressure-induced phase separation, which is related with a lattice distortion from the tilting of the CuO6 octahedra.