Temperature And Plane Field Domains In Garnet Bubble Films Part Ii Class Dumbbell

The ultra-high-density Bloch line memory (BLM) uses negative vertical-Bloch-line (VBL) pairs in the walls of hard domains as information carriers. It is important to investigate the stability of the vertical-Bloch-lines for developing the BLM and enriching the theory of Magnetic domain walls. The temperature and in-plane field, the two important factors, will affect the vertical-Bloch-lines in hard domains. The critical temperatures and the critical in-plane fields for the annihilation of the VBLs, related to materials parameters, have been discovered. Huo et al. have investigated the ordinary hard bubbles (OHBs) are subjected to joint temperature and in-plane field and find some important rules of the annihilation of the VBLs. QHBs contain the fewest numbers of VBLs in three kinds of hard domains, while the first kind of the dumbbell domain (IDs) and the second kind of dumbbell domain (IIDs) contain greater numbers of VBLs. What are the rules of IIDs subjected to joint temperature and in-plane field? This is the reason of my paper.My work is narrated briefly as followed:In this experiment, firstly, generate hard domains with a large percentage of IIDs by applying a series of pulses; apply various temperatures, and measure the critical temperatures and critical in-plane fields for the annihilation of the VBLs. It is found that there exists acritical in-plane field range [Hip(1) (T) ,Hip(2)(T)], depending on temperature. The VBLs in the walls of IIDs annihilate gradually in this critical in-plane field range. Also the critical in-plane field range [Hip(1)(T),Hip(2)(T)], the critical in-plane field Hip(1)(T) and Hip(1)(T) all decreasewith the temperature increasing. It confirms that the VBLs in the domain walls will be unstable when they are subjected to spray field and in-plane field with the temperature increasing.The annihilation of VBLs in the walls of IIDs, containing greatest numbers of VBLs in three kinds of the hard domains, is more complex. So this experiment is benefit to discuss the annihilation of VBLs in the hard domain walls and it offers the experiment facts to the theory of the hard domain walls.Secondly, the method of formation hard domains is the essential prerequisite to study the character and stability of hard bubbles. So it is necessary to study the formation of the harddomains in the small size bubbles. "Pulses method" and "low-bias-field method" are two effective ways to form the hard domains. We find that it is difficult to form small-size bubbles in garnet films of some nominal compositions by "pulses method', but easier by "low-bias-field method". Moreover, it is found that the thickness of the same nominal compositions of garnet films affects the numbers of hard domains under low bias fields and series pulse. The investigation gives a way to form small-size bubbles, as well as offers much experiment facts to explore the formation mechanism of VBLs.