OPTICAL-ABSORPTION OF BISRCACUO FILMS

Optical absorption spectra of amorphous and crystalline films of Bi1,8 Pb0,2Sr2Ca2Cu3O10+x (phase 2223) and Bi2Sr2Ca1Cu2O8+x (phase 2212) are investigated. The spectrum profile is found to be sensitive to film s tructure. A long-wave region of the absorption spectra of the crystall ine films displays an area associated with the absorption by free char ge carriers, the absorption coefficient in this area being proportiona l to the product of metal phase concentration by hole concentration. T he position of the minimum in the absorption spectra (its limiting val ues are 1.25 eV for the films of phase 2223 and similar to 1.15 eV for these of phase 2212) is related to that of the Fermi level. Examples of application of the results obtained in the estimation of metal phas e and hole concentrations are demonstrated.