Rearrangement of emission spectra of the oxygen subsystem in Y–Ba–Cu near the superconducting transition
Аннотация
Luminescence investigations of the temperature behavior of Y–Ba–Cu superconducting samples excited by an electron beam are carried out. Narrow-band peaks at 3.3 eV and wide-band maxima near 3.1 and 2.5 eV associated with oxygen–copper subsystem are singled out in the emission spectrum. It is found that at the superconducting transition point Tc, the rearrangement of the emission spectrum takes place: the narrow-band peaks are abruptly suppressed, the intensity in the 2.6 eV band is enhanced, and atomic lines of neutral oxygen emerge (atomic oxygen is expelled from the sample). The observed changes in the electron spectrum of Y–Ba–Cu together with hysteresis effects in the temperature dependence of radiation confirm the energy and structure arrangement of the oxygen subsystem at Tc, which is a phase transition of the second kind close to the first.
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