Magnetic flux motion in ( P r x Y 1 − x ) B a 2 C u 3 O 7 − δ polycrystal samples sintered in Ar and O2 atmospheres

We present a comparative study of the magnetic flux motion in ceramic pellets made of ( P r x Y 1 − x ) B a 2 C u 3 O 7 − δ as a function of their composition and morphology. Samples produced in Ar or O2 atmosphere present noticeable differences in their magnetic response that we explain in terms of their structural parameters. The material’s parameters that most influence the flux dynamics are morphology and oxygen content, that change dramatically with the sintering atmosphere. Moderate changes are also observed as a function of the Pr content. Magnetic pinning efficiency is discussed in terms of intergranular couplings and effective activation energies, estimated from AC-susceptibility and magnetoresistance measurements.