STRUCTURAL-CHANGES ON THE STRUCTURE OF Y2BA4CU7O15-D WITH PR SUBSTITUTION

Powder neutron diffraction data have been collected for a series of Y2 -xPrxBa4Cu7O15-d samples with x = 0.0, 0.4 and 0.8. A solubility limit of about x = 1.0 was found in samples sintered at one atmosphere oxyg en pressure. Structural investigations show an overall expansion of th e unit cell and a slight decrease of the orthorhombicity. Also, the di stance between the CuO2 planes increases. A possible charge transfer e ffect may be deduced from the movement of the apical oxygens.