Second Kind Of Dumbbell Domains Research Articles

Influence of temperature on the critical in-plane field range for VBLs in the walls of hard domains

The influence of temperature on the critical in-plane field range for vertical Bloch lines in the walls of three kinds of hard domains is investigated experimentally. It is found that for each kind of three hard domains, there exists a critical in-plane field range, i. e. [ H ip ( 1 ) ( T ) , H ip ( 2 ) ( T ) ] , which depends on temperatures and in which vertical Bloch lines are unstable. Here, H ip ( 1 ) ( T ) is the initial critical in-plane field where VBLs in the walls of three kinds of hard domains are annihilated, and H ip ( 2 ) ( T ) is the lowest in-plane field where VBLs in their corresponding hard domains are annihilated completely. H ip ( 1 ) ( T ) , H ip ( 2 ) ( T ) and [ H ip ( 1 ) ( T ) , H ip ( 2 ) ( T ) ] , all decrease as the temperature increase. Furthermore, H ip ( 1 ) ( T ) and H ip ( 2 ) ( T ) reach zero at T 0 1 and T 0 , respectively. In addition, there exists a relationship among them, when T is unchanged, H ip ( 1 ) ( T ) of the three kinds of hard domains (ordinary hard bubbles (OHB), first kind of dumbbell domain (ID) and second kind of dumbbell domains (IID)) decrease successively, and their H ip ( 2 ) ( T ) are the same.

Influence of in-plane field on vertical Bloch line in the walls of the second kind of dumbbell domains at various temperatures

The stability of vertical Bloch lines (VBLs) in the second kind of dumbbell domain (IIDs) walls in liquid phase epitaxy garnet bubble films subjected to an in-plane field at various temperatures is studied experimentally. It is found that there exists a critical in-plane field range depending on temperature, in which vertical Bloch lines (VBLs) in the second kind of IIDs walls are unstable, i.e., [Hip(1)(T),Hip(2)(T)]. Here, Hip(1)(T) is the initial critical in-plane field at which VBLs in the walls of IIDs annihilate; while Hip(2)(T) is the lowest in-plane field at which all VBLs in the walls of IIDs have annihilated completely. Also, the critical in-plane field range [Hip(1)(T),Hip(2)(T)],Hip(1)(T) and Hip(2)(T) all decrease with the temperature increasing. Hip(1)(T) and Hip(2)(T) reach zero at T0′ and T0, respectively.

Influence of rotating in-plane field on vertical Bloch lines in the walls of second kind of dumbbell domains

Influence of rotating in-plane field on vertical Bloch lines in the walls of second kind of dumbbell domains (IIDs) was investigated, and a critical in-plane field range [ H ip 1, H ip 2] of which vertical-Bloch lines (VBLs) annihilated in IIDs is found under rotating in-plane field ( H ip 1 is the maximal critical in-plane-field of which hard domains remain stable, H ip 2 is the minimal critical in-plane-field of which all of the hard domains convert to soft bubbles (SBs, without VBLs)). It shows that the in-plane field range [ H ip 1, H ip 2] changes with the change of the rotating angle Δ ϕ. H ip 1 maintains stable, while H ip 2 decreases with the decreasing of rotating angle Δ ϕ. Comparing it with the spontaneous shrinking experiment of IIDs under both bias field and in-plane field, we presume that under the application of in-plane field there exists a direction along which the VBLs in the domain walls annihilate most easily, and it is in the direction that domain walls are perpendicular to the in-plane field.

Formation of three kinds of hard domains by low-bias-field method

The formation of three kinds of hard domains (HDs) at low bias field was studied experimentally. Low-bias-field method provides a simple way to produce the three kinds of HDs in different proportions. Also, the relationship between the shape of the multi-branched domains (MBDs) and the different kinds of domains was studied. Most branches of the MBDs correspond to the first kind of dumbbell domains or the second kind of dumbbell domains; in contrast, few branches of the MBDs correspond to the hard bubbles or soft bubbles.

Influence of crystal directions on the annihilation of Vertical Bloch Lines in the Second kind of dumbbell domains under in-plane field

Influence of crystal directions on the annihilation of Vertical Bloch Lines in the Second kind of dumbbell domains under in-plane field

Annihilation of vertical-Bloch-line chains in the walls of the second kind of dumbbell domains subjected to joint static bias field and in-plane field

Experiments were statistically carried out on the behavior of vertical-Bloch-line (VBL) chains in the walls of the second kind of dumbbell domains (IIDs) is garnet bubble films subjected to joint action of static bias field H-b and in-plane field H-ip. The curves of the four critical in-plane fields, (H-ip)(IID-ID) (Hip)(IID-OHB) (Hip)(IID-SB) and H-ip' vs H-b were measured and explained. In particular, in terms of two series of IID photos, a new experimental manifestation of the unknown number effect of VBL chains was found.

Stability of second kind of dumbbell domains subjected to an in-plane field at different bias fields

The softening process of the second kind of dumbbell domains(IIDs) in garnet bubbles films subjected to an in-plane field Hip at different static bias field Hb was studied experimentally. It was found that when Hb is larger, the remaining percentage of IID, RIID, drops sharply at a certain Hip, and with the increase of Hb the drop occurs at lower Hip and becomes more intensive. We have confirmed that this is related to the spontaneous-shrink of IIDs, which plays an important role for the breakdown of vertical Bloch line chains of IIDs subjected to joint fields Hip and Hb.

Stripe-to-bubble transition of the second kind of dumbbell domains subjected to both static bias field and in-plane field

Stripe-to-bubble transition (SBT) of the domains that are transformed from the second kind of dumbbell domains (IIDs), which are subjected to an in-plane field H ip in a fixed static bias field H b, was studied experimentally. The results suggest that H b plays an important role in SBT. There are four characteristic static bias fields from low to high, ( H b) h, ( H b) I, ( H b) II and ( H b) c. When H b<( H b) h, a high H ip has to be applied so that SBT can take place. The H ip increases as H b decreases. In fact, in this case, before SBT takes place, all of the IIDs lose all their vertical Bloch lines (VBLs), and transform to soft domains. When H b is higher than ( H b) h and ( H b) I, the ordinary hard bubbles (OHBs) and the first kind of dumbbell domains (IDs) begin to appear in the domains transformed from IIDs, after SBT takes place. When H b>( H b) II, some of the IIDs collapse in stripe shape, at a low H ip, instead of SBT. The percentage of IIDs that collapse in stripe shape increases rapidly as H b increases. It increases to 100% when H b=( H b) c. It is suggested that, in this case, all VBLs in IIDs walls break down at the same time instead of losing gradually. This phenomenon may act as a clue to the further research of the mechanism of the VBLs breaking down when subjected to both H b and H ip.

The annihilation of VBLs in the walls of second kind of dumbbell domains to which bias fields and in-plane fields are alternately applied

The annihilation of vertical Bloch lines in magnetic domain walls of the second kind of dumbbell domains, to which both bias fields and in-plane fields are alternately applied, are investigated experimentally. A critical in-plane field range [ H ip (0), H ip′] is found. We hypothesize that there exists a direction along which the vertical Bloch lines in the domain walls annihilate most easily. It is observed that the annihilation of vertical Bloch lines in the domain walls does not depend on the initial state. This provides a more detailed description of the minimum critical in-plane field than obviously known.

The influence of temperature on vertical Bloch lines in the walls of hard domains in the uncompressed state

The temperature stability of vertical Bloch lines in the walls of the second kind of dumbbell domains and selected ordinary hard bubbles is investigated experimentally. By analysing systematically the influence of temperature on vertical Bloch lines in the walls of ordinary hard bubbles, the first kind of dumbbell domains and the second kind of dumbbell domains, we obtain the general rules of annihilation of vertical Bloch lines in the walls of hard domains subjected to temperature in the uncompressed state.

The behaviour of the first kind of dumbbell domains with both static bias field and temperature

Two varieties of the first kind of dumbbell domains have been discovered in materials with the nominal composition (YSmLuCa) 3(FeGe) 5O 12. One of the two varieties produces self-shrinking, while the other does not. The relationship between self-shrinking and temperature is studied. It is also shown that VBLs in the dumbbell domains in the material experience gradual annihilation. Experiments on a material of composition (YSmCa) 3(FeGe) 5O 12 have shown that the stability of the dumbbell domains are dependent on composition. We also explain why materials with Lu can not produce the second kind of dumbbell domains.

Annihilation of vertical-Bloch-line chains in the walls of the second kind of dumbbell domains subjected to an in-plane field

An experiment was statistically performed on the annihilation of vertical-Bloch-line (VBL) chains in the walls of the second kind of dumbbell domains (IIDs) subjected to an in-plane field Hip. It was again confirmed that there is a critical in-plane field H'ip, above which all VBL chains of hard domains in garnet bubble films, including IIDs, disappear. Just like ordinary hard bubbles (OHBs), it was also found that there exists a critical range of Hip, from (Hip)ID to H'ip, for IID softening. Over this range, with the increase of Hip, more and more IIDs are softened, accompanied by the successive appearance of the first kind of dumbbell domains, OHBs and soft bubbles. In addition, for the five samples tested, the ratio, H'ip/(Hip)ID, is obviously greater than √2.