Novel asymmetric critical state in YBa2Cu3O7-delta with columnar defects

We studied the critical state field profile using magneto-optical technique in YBa2Cu3O7-delta With columnar defects (CDs) when the field is tilted aw ay from CDs. We observed an asymmetric critical state field profile with th e current discontinuity line (d-line) considerably away from the center of the sample. The shift of the d-line from the center (Delta y) has symmetric hysteresis loop with respect to H = 0. When the field sweep direction is c hanged, the previous d-line disappears and a new d-line is generated at the opposite side. The shift of the d-line is parallel to the tilting plane of H and toward the direction of the misalignment of H from CDs. We interpret this asymmetry as caused by the in-plane magnetization, which is originate d from the alignment of vortices to CDs. The field dependence of Delta y is discussed in relation with the correlation length of vortices along CDs.