The Study Of Characteristic Of The Hard Domains In Garnet Bubble Films

In this paper we have studied the dynamic characteristics and temperature-characteristics of hard domains that are produced by the low bias field method, and also make a study of the generant condition of the positive or negative VBLs that are produced by the low bias field method.First, the dynamic characteristics of multi-branched domains that can collapse in hard domains are studied, and the results are different from the results that obtained by using series of pulse bias fields method: The hard domains that were produced by series of pulse bias fields method will rotate like a windmill when direct current bias fields rise to Hsb' and pulseis added to the hard domains. With the width of hardening pulse TP rising, the direction of rotation changed from all ofclockwise through part of clockwise and part of anticlockwise to all of anticlockwise. The range of pulse (Hp)h and the number of pulse (np)h don't affect the direction. However, with the direct current bias field Hb rising, the direction of rotation changed from all of clockwise through part ofclockwise and part of anticlockwise to all of anticlockwise. The range of pulse (Hp)h the width of pulse tp and the number of pulse (np)h don't affect the direction. We thought that was because of the characteristics of the VBL chains in the wall of the hard domains. Analyzed and contrasted with them, we come to a conclusion: the formation of the negative VBL chains are corresponding with the descended pulses, and the formation of the positive VBL chains are related to the rise pulses. We also demonstrate the rule of them.Then, we studied the effect on formation of the VBL chains when they are subjected with temperature. The threshold temperature T10 at which the VBL chains begin to breakdown and the critical temperature T0 at which the VBL chains breakdown completely of the second kind of dumbbell in garnet bubble films in the uncompressed state were measured in detail. We found that the threshold temperature T10 and the critical temperature T0 change when the direct current bias field is equal to a certain value. At the same time we observed the shape of the multi-domains at different temperature. When thetemperature is higher than the critical temperature T0, the shape of multi-domains is still little different from the multi-domains which produced at room temperature, so we think that the fractal theory is unfit for studying multi-domain's hardness.Finally, Based on experiment above, we measured the variation of collapse field of the multi-domains that produced at different temperature and the distribution of the four kinds of domains that was shrank by the multi-domains at different temperature. We also measured the variation of collapse field of the multi-domains at room temperature that produced at different temperature, and the distribution of the four kinds of domains correspondingly. It indicated that IID, ID, OHB and SB appear one after another with the temperature rising. It means that the higher the temperature is, the less the VBL chains in the domain are, so the softer the domains are.