Abstract:
Polycrystalline samples of the Pr doped Yb1−xPrxBa2Cu3O7− (i.e. Yb(Pr)-123) system
for 0 x 1 have been investigated for resistivity and magnetization M as a
function of temperature in normal and superconducting states. The gradual decrease
in superconducting critical temperature Tc(x) is found to be correlated with the xdependent
ratio of resistivity slope (d =dT )cc (corresponding to the linear (T) region)
and residual resistivity 0. In particular, the observed di erence of critical Pr concentration
where superconductivity is destroyed (xc) in Yb(Pr)-123 (xc 0:65) and Y(Pr)-123
(xc 0:55) matches with the di erence in the value of Pr concentration where the ratio
(d =dT )cc= 0 tends to go to zero in them. The M(T) data of the Yb(Pr)-123 samples
show magnetic ordering for x > xc at characteristic temperatures, Tn, that increase
with x. Interestingly, the Yb(Pr)-123 sample with Pr content (x = 0:6) near xc reveals
several anomalous features like transition from metallic to semiconducting-like (T), an
excessive broadening of the diamagnetic transition and weakening of the M(T) signal
related to antiferromagnetic ordering of Pr ions. These observations can be consistently
interpreted by assuming the presence of dynamically fluctuating striped phase in these
systems.
