Stability of vertical‐bloch‐line chains in the walls of the first kind of dumbbell domains subjected to static bias field at various in‐plane fields

Abstract

AbstractFor the first kind of dumbbell domains (IDs) of garnet bubble films, the annihilating process of vertical bloch line chains (VBLs) subjected to an in‐plane field ($ H_{\rm ip} $) at various static bias fields ($ H_{\rm b} $) was experimentally studied. Three important relations have been obtained, which are the relations between $ H_{\rm ip}^{(1)} $, $ H_{\rm ip}^* $, $ H_{\rm ip}^{(2)} $ and $ H_{\rm b} $. here, $ H_{\rm ip}^{(1)} $ is the initial critical in‐plane field where VBLs in the walls of IDs are annihilated, i.e. some of the ID begin to be softened, $ H_{\rm ip}^* $ is designated as the in‐plane field where ID begins to soften to SB and $ H_{\rm ip}^{(2)} $ is the lowest in‐plane field at which all VBLs in the walls of IDs annihilate completely. by the experiment of the so‐called “tail‐cut”, it is found that each $ H_{\rm ip} $ from $ H_{\rm ip}^{(1)} $ to $ H_{\rm ip}^{(2)} $ corresponds to a certain length of VBL chains in the walls of IDs. the higher $ H_{\rm ip} $, the shorter the VBL chains. $ H_{\rm ip}^{(1)} $ and $ H_{\rm ip}^{(2)} $ correspond to the longest and shortest VBLs, respectively. it is also found that both $ H_{\rm ip} $ and $ H_{\rm b} $ play an important role during the annihilating of vbl chains in the walls of IDs. If $ H_{\rm b} $ is lower, $ H_{\rm ip}^{(1)} $, $ H_{\rm ip}^* $ and $ H_{\rm ip}^{(2)} $ are unchanged. with increasing $ H_{\rm b} $, especially being close to or higher than the standard stripe‐to‐bubble transition field ($ H_{\rm sb} \prime $), they all rapidly decrease. And they do not change further when $ H_{\rm b} $ is a little higher than the minimum collapse field of OHBs ($ H_0 \prime $). (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)