Sj. Liu et Wy. Guan, SPIN GAP IN THE NORMAL-STATE OF PR-DOPED AND OXYGEN-DEFICIENT RBA2CU3O7 SUPERCONDUCTORS, Physical review. B, Condensed matter, 58(17), 1998, pp. 11716-11720
The spin-gap temperatures (T-S) in the normal state of bulk Pr-doped R
Ba2Cu3O7 (R1-xPTxBa2Cu3O7) and oxygen-deficient RBa2Cu3Ox (R = Yb, Er,
Y, Ho, Dy, Gd, Eu, Sm, and Nd) are investigated. The elements on the
R sites and the distance between CaO2 planes are found to have no infl
uence on T-S in oxygen-deficient RBa2Cu3Ox in terms of the relationshi
p between the superconducting temperature (T-C) and T-S. However, for
R1-xPrxBa2Cu3O7, T-S increases with increasing ionic size of R-site el
ements for a fixed Pr concentration. Furthermore, by comparing T-S of
oxygen-deficient RBa2Cu3Ox to that of R1-xPrxBa2Cu3O7 at the same T-C,
it is observed that Pr atoms doped on the R sites not only reduce the
carrier density and induce the spin gap, but will also simultaneously
suppress T-S. [S0163-1829(98)05837-8].