Patent ID: 7821366

Claim:
A magnetic circuit for storing a magnetic recording medium in a gap formed between a plurality of magnetic field application parts opposed to each other in parallel and applying a magnetic field to the magnetic recording medium, wherein each of the magnetic field application parts is configured by combining a plurality of permanent magnet segments, the permanent magnet segments include a first permanent magnet horizontally magnetized in parallel with an opposed surface of the magnet field application part, a second permanent magnet magnetized perpendicularly to the opposed surface of the magnetic field application part, the second permanent magnet being provided on a north pole of the first permanent magnet, a third permanent magnet perpendicularly magnetized in an opposite direction from the second permanent magnet, the third permanent magnet being provided on a south pole of the first permanent magnets, and wherein the magnetic field application parts are configured like a ring around a virtual axis with a combination of the plurality of first to third permanent magnets, the first permanent magnet is disposed such that the first permanent magnet is magnetized along a direction transverse to the virtual axis, and the first permanent magnet is longer than the second permanent magnet and the third permanent magnet in a direction transverse to the virtual axis.