The dynamics of domain walls in (110) oriented manganese containing garnet films have been studied. Bubble films and special films in which a single straight domain wall can be stabilized have been prepared. The magnetic anisotropy in these films is orthorhombic and the influence of the in-plane anisotropy field on the maximum domain-wall velocity has been studied. The observed maximum velocities, varying between 40 and 1500 m s−1, are usually considerably lower than the maximum velocities predicted by theory. However, for very high in-plane anisotropy fields the experimental maximum velocities approximate the theoretical ones. From the comparison of different samples it has been concluded that the maximum velocity of the bubbles having no Bloch lines is not very different from the maximum velocity of straight domain walls. Furthermore, it has been shown that the maximum velocity is independent of the film thickness. The influence of external in-plane fields on the maximum velocity also has been studied. In-plane fields in the hard direction of magnetization have no influence on the maximum velocity. In-plane fields small compared with the in-plane anisotropy field increase the maximum velocity considerably if these in-plane fields are applied in the direction perpendicular to the hard axis of magnetization. The influence of stray fields on the maximum velocity is discussed.

Two high speed photograpy techniques for studying moving domain walls in magnetic bubble materials are given. The capabilities of both techniques are demonstrated and the advantages and disadvantages of both techniques are discussed.

The static properties of bubbles in (110) oriented garnet films of composition (Gd, Y)3 (Fe, Mn, Ga)5O12 have been studied. The anisotropy in these films is orthorhombic with the easy axis of magnetization perpendicular to the plane of the film and a secondary easy axis in the plane of the film. Two types of bubbles can be distinguished, A-type bubbles having no Bloch lines and B-type bubbles with Bloch lines. Magnetic fields parallel to the in-plane easy axis of magnetization have a strong influence on the diameter and on the collapse field. Whereas the properties of the B-type bubbles are independent of the sign of this in-plane field, the properties of the A-type bubbles do depend on the sign of this in-plane field. B-type bubbles easily change state and become A-type under influence of in-plane fields. At zero in-plane field the collapse fields of B-type bubbles are about 1 to 3% larger than the collapse fields of A-type bubbles. A theory is presented that takes into account the interaction between in-plane field and domain wall magnetization. In this way the experimental data obtained for the A-type bubbles are reproduced very well. The difference between the collapse fields of A- and B-type bubbles in zero in-plane field is explained by taking into account the influence of stray fields and Bloch lines on the domain wall energy.