Magnetic recording medium and magnetic storage apparatus
View Patent ↗A magnetic recording method for recording information on a medium with a first magnetic layer, a second magnetic layer, and a non-magnetic coupling layer provided between the first and second magnetic layers so that these two layers are exchange-coupled and the first magnetic layer has an exchange coupling field Hex 1 larger than both a coercivity Hc 1 of the first magnetic layer and a coercivity Hc 2 of the second magnetic layer. The method includes limiting a magnetic field applied to the magnetic recording medium during recording to a range so that magnetizations of the first and second magnetic layers are maintained in either a first antiparallel state or a second antiparallel state, without entering into a parallel state, whereby in the second antiparallel state the magnetizations of the first magnetic layer and the second magnetic layer are reversed, but still antiparallel, relative to the magnetization in the first antiparallel state.
1. A magnetic recording method for recording information on a magnetic recording medium comprising a first magnetic layer, a second magnetic layer, and a non-magnetic coupling layer provided between the first magnetic layer and the second magnetic layer so that the first and second magnetic layers are exchange-coupled and the first magnetic layer has an exchange coupling field Hex 1 that is larger than both a coercivity Hc 1 of the first magnetic layer and a coercivity Hc 2 of the second magnetic layer, said magnetic recording method comprising:
limiting a magnetic field that is applied to the magnetic recording medium during a recording process to a range such that magnetizations of the first magnetic layer and the second magnetic layer are maintained in either a first antiparallel state or a second antiparallel state, without entering into a parallel state, whereby in said second antiparallel state the magnetizations of the first magnetic layer and the second magnetic layer are reversed, but still antiparallel, relative to the magnetization in said first antiparallel state.
2. The magnetic recording method as claimed in claim 1 further comprising:
using a coupling intensifying region, provided near a boundary of said non-magnetic coupling layer and at least one of said first and second magnetic layers, for intensifying an exchange coupling strength between said first magnetic layer and said second magnetic layer.
3. The magnetic recording method as claimed in claim 1 , further comprising:
using a first coupling intensifying region, provided near a boundary of said first magnetic layer and said non-magnetic coupling layer, for intensifying an exchange coupling strength between said first magnetic layer and said second magnetic layer; and
using a second coupling intensifying region, provided near a boundary of said second magnetic layer and said non-magnetic coupling layer, for intensifying the exchange coupling strength between said first magnetic layer and said second magnetic layer.
4. The magnetic recording method as claimed in claim 2 , wherein the coupling intensifying region includes a material dispersed within a surface portion of at least one of said first and second magnetic layers at the boundary of said non-magnetic coupling layer and at least one of said first and second magnetic layers.
5. The magnetic recording method as claimed in claim 1 , wherein said magnetic recording medium includes a recording surface, the magnetic recording method further comprising:
recording to a plurality of unit recording portions on said recording surface, said unit recording portions having boundaries which are separated from adjacent unit recording portions, wherein each of said plurality of unit recording portions has a stacked structure formed by said first magnetic layer, said non-magnetic coupling layer and said second magnetic layer.