Magnetic recording medium capable of reproducing information by displacing magnetic wall and recording-reproducing method therefor
US6403205B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 14, 2000 |
| Grant date | Jun 11, 2002 |
| Priority date | — |
| Expiry date | Jul 14, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/265
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magnetic recording medium including first, second and third magnetic layers laminated in succession, wherein (1) when the magnetic wall energy density, saturation magnetization, magnetic wall coercivity and film thickness of the first magnetic layer at a temperature T represented by cgs unit system are defined as &sgr;1, Ms1, Hw1 and h1, respectively, (2) the magnetic wall energy density, saturation magnetization, magnetic wall coercivity and film thickness of the third magnetic layer are defined as &sgr;3, Ms3, Hw3 and h3, respectively, (3) the interface magnetic wall energy, density between the first magnetic layer and the third magnetic layer is defined as &sgr;w13, and (4) the lowest temperature at which &sgr;w13 is 0 erg/cm2 is Ts,2Ms1*Hw1<&sgr;w13/h1and2Ms3*Hw3>&sgr;w13/h3are satisfied at room temperature, andwhen a suitable temperature Tp is chosen, within a temperature range greater than the temperature Ts and lower by 10° C. or more than the Curie temperature Tc1 of the first magnetic layer,within a temperature range of about Ts to Tp,k1(T)<k3(T)and are satisfied,wherek1(T)=(2Ms1*Hw1+&sgr;w13/h1)/|d&sgr;1(T)|k3(T)=(2Ms1*Hw3−&sgr;w13/h3)/|d&sgr;3/dT|.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.