Break-Down of Vertical-Bloch-Line Chains in Ordinary Hard Bubble Walls Subjected to an In-plane Field

An experimental and theoretical study was carried out on the break-down of vertical-Bloch-line (VBL) chains in ordinary hard bubble walls subjected to an in-plane field, H_ip. Other than a single critical value, a critical range of in-plane field, from H⁽¹⁾_ip to H⁽²⁾_ip, was found. When H_ip< H⁽¹⁾_ip the VBL chains keep unchanged; whereas when H⁽¹⁾_ip < H_ip < H⁽²⁾_ip, more and more hard domains are softened. Above H⁽²⁾_ip all VBL chains are broken-down. A theoretical analysis showed that the critical range of H_ip is originated from the serpentine curving of domain walls, and a relation H⁽²⁾_ip / H⁽¹⁾_ip=√2, was obtained, which is in good agreement with the experiments.