A core and valence level photoemission study of Y1-xPrxBa2Cu3O7

Abstract Core and valence level photoemission spectra of the 123 oxides Y 1− x Pr x Ba 2 Cu 3 O 7 have been measured over the complete composition range 0 x 3 and BaPr 2 O 4 with those of PrBa 2 Cu 3 O 7 suggest a Pr(III) valence state in the 123 compound. There was a progressive increase with Pr doping in the intensity of the photoemission structure excited with 21.2 eV radiation in the upper part of the valence band. This observation is discussed in relation to the Pr 4f/O 2p mixing thought to be responsible for the metal to non-metal transition in this system.