Abstract: Herein disclosed is a magnetic garnet film for a magnetic bubble element, in which the temperature changing rate of a bubble collapse field is reduced by Gd and Ga and in which the operating characteristics of the bubbles are improved by La and Lu. The temperature coefficient of the bubble collapse field is -0.24 to 0%/.degree. C., and the operating characteristics are remarkably excellent, therefore, this garnet film is suitable for the small bubbles with a diameter smaller than or equal to 1 .mu.m.

Abstract: A magnetic bubble memory device and a method of fabricating the device are disclosed in which a conductor pattern lies at least between a film for maintaining magnetic bubbles therein, and a soft magnetic material pattern. Further, the magnetic bubble memory device can be formed precisely without suffering from errors due to mask alignment, by employing a mask provided with a plurality of patterns which are different in transmittance.

Abstract: A magnetic garnet film for a magnetic bubble memory device in which parts of rare earth element and iron are replaced by predetermined quantities of Gd and Ge, respectively. The garnet film exhibits very small temperature-dependency of the bubble collapse field as well as high Curie temperature, whereby magnetic bubbles of very small diameter can be sustained and controlled with stability over a wide temperature range.

Abstract: A garnet film for a magnetic bubble domain device which comprises a predetermined quantity of Gd and a predetermined quantity of Ga.The garnet film has a temperature coefficient of not more than 0.2%/.degree.C. in respect of the bubble collapse field owing to the addition of Gd and Ga and is suitable for substaining small magnetic bubbles of a diameter of less than 2.5 .mu.m.

Abstract: A magnetic bubble memory device is disclosed in which a hardened film made of a heat-resisting highly-polymerized organic resin and having a predetermined thickness is employed for an insulating film interposed between a conductor pattern and a soft magnetic material pattern. In a conventional magnetic bubble memory device in which the above-mentioned insulating film is made of SiO.sub.2, an abrupt step is produced in the soft magnetic material pattern due to the existence of the conductor pattern beneath a portion of the soft magnetic material pattern, and the margin of bias magnetic field is thereby lowered. According to the present invention, the step is reduced and smoothed, and thus the lowering of the margin can be prevented.

Abstract: A field access magnetic bubble memory device including a memory chip applied with an in-plane magnetic field at need is disclosed. At a transient stop operation of the device before its interrupted state, an in-plane field is removed after it has been held for a predetermined period following the cessation of rotation thereof. The in-plane field may be increased upon the cessation of rotation thereof. At a transient start operation of the device after the interrupted state, an in-plane field having no rotation and the same direction as at the transient stop operation is applied for a predetermined period before the initiation of rotation thereof. The applied in-plane field may be increased upon the initiation of rotation thereof.

Abstract: A polycrystalline film made of a ferromagnetic substance is deposited on a magnetic film to form a composite magnetic film. The composite magnetic film, unlike a conventional single-layered magnetic film made only of a Garnet film, is free from development of hard bubbles and has very excellent characteristics as magnetic film for use in a magnetic bubble device.