STRUCTURAL, MAGNETIC AND ELECTRICAL STUDIES ON PR(BA1-XSRX)2CU2NBO8-Y

Structural, magnetic and electrical properties of Pr(Ba1-xSrx)2Cu2NbO8 -y, having a similar structure to PrBa2Cu3O7-y but with NbO2 planes re placing the CuO chains, are investigated by means of X-ray diffraction , magnetic susceptibility and electrical resistivity experiments. Only a small diffraction peak was observed to grow when substituting Sr fo r Ba. The decrease of the lattice parameters a, c and V with x in Pr(B a1-xSrx)2Cu2NbO8-y following Vegard's law may indicate the same crysta l structure for both end members. The antiferromagnetic-transition tem perature T(N) for PrBa2Cu2NbO8-y determined from the peak in the tempe rature dependence of magnetic susceptibility decreases rapidly with in creasing Sr concentration. Also as the Sr concentration is increased, the effective paramagnetic moment mu(eff) of the Pr ion is enhanced, w hile the electrical resistivity is reduced. These results are discusse d in conjunction with the structural aspect, hybridization and magneti c coupling mechanism for these Pr-based cuprates.