An external magnetic field device for a magnetooptical information recording and reproducing apparatus.

摘要

An external magnetic field device for a magnetooptical information recording and reproducing apparatus in which an external magnetic field to be applied to a magnetooptical information recording medium is modulated by supplying to a magnetic head (3) an alternate current the polarity of which is changed according to information to be recorded. The device comprises an offset circuit (2) for producing an offset in the alternate current. The direction of the offset is selected so as to increase the current level of the polarity by which the initial magnetization of the information recording medium (4) is reversed. The direction of the offset may be selected so as to cancel the leakage magnetic field.