| 摘要 |
PURPOSE:To switch a large magnetic field at a high speed by providing a permanent magnet and a core part made of a high magnetic permeability magnetic material which has at least one part opposite to the magnetic pole of said magnet and a coiled part. CONSTITUTION:The titled device is constituted of the plate-like permanent magnet 22 and the core part 23 made of the L-type high magnetic permeability magnetic material composed of the part opposite to one magnetic pole of the magnet 22 and the coil 24, which is connected to a current source 24. When a current flowing to the coil 24 does not flow, the core part 23 forms a magnetic path leading the flux generated from one magnetic pole of the magnet 22 to other magnetic pole as shown in figure (a), whereby a magnetic field will not be impressed downward the core part 23. On the other hand, when the current I flows in the coil 24, only the flux component caused by the current I leaks outside from the magnetic pole of the magnet 22, and a bias magnetic field is impressed in the vertical direction downward the core part 23. Accordingly, when a recording medium 1 is disposed downward the core part 23, the impression of the magnetic field to the medium 1 in the vertical direction can be controlled by a coil current. |
