Abstract
Flux-pinning in Y 0 . 5 /Nd 0 . 5 (123) melt-textured growth sample that had been doped with excess 20wt.% Y 1 /Nd 1 (211) and 0.5 wt.% PtO 2 has been analyzed by means of a scaling approach. The different parameters of scaling, irreversibility field (B . i r r ), magnetic field (B j p ) and current density(J p ) of the fishtail peak effect, and the field (B f p ) corresponding to the maximum pinning force density (F p , m a x ), were determined using the measurements of magnetically induced current density as a function of field and temperature. For the commonly used scaling of normalized volume pinning force, (F p = J c xB a )/F p , m a x , versus reduced magnetic fields h=B a /B i r r , (where B a stands for applied magnetic field), the curves collapse into a universal curve with a peak corresponding to h=0.44. Based on the approach of Dew-Hughes [1], we interpret the position of this peak as a clear indication of a δT c -pinning type. Similar scaling was also obtained with the use of B p f instead of B i r r , but poor scaling was obtained with the use of J p . Our results are compared with those for other Re (123) systems.