Critical state of YBa 2Cu 3O y disc in perpendicular fields

Abstract

We have studied the critical state of a disc shaped YBa 2Cu 3O y film in perpendicular magnetic fields through precise measurements and analyses of magnetization curves. At low temperatures 20 K ≤ T ≤ 40 K and in low magnetic fields B a ≤ 0.3 T, the magnetization curves of the YBa 2 Cu 3 O y disc were well described by recent calculations performed by Mikheenko et al., Zhu et al. and Clem et al. assuming Bean's critical state model in perpendicular fields. Furthermore, we demonstrated the direct observation of magnetic hysteretic behavior described by the critical state model.