Magnetic recording medium, method of manufacturing the same, and magnetic recording/reproducing apparatus
View Patent ↗The present invention provides a magnetic recording medium which is capable of improving the perpendicular orientation of a perpendicular magnetic recording layer while maintaining a writing performance during recording and obtaining both an improvement in the perpendicular orientation and fine magnetic crystal particles with a uniform diameter, and which enables information to be recorded or reproduced at high density, a method of manufacturing the same, and a magnetic recording/reproducing apparatus. A magnetic recording medium 10 according to the present invention includes at least a soft magnetic underlayer 2 , an orientation control layer 3 , a magnetic recording layer 4 , and a protective layer 5 formed on a non-magnetic substrate 1 . The orientation control layer 3 has a seed layer 6 and an intermediate layer 7 . The seed layer 6 is made of a Cu—Ti alloy that has a face-centered cubic structure and includes Cu as a main component. The Cu—Ti alloy has a (111) crystal plane oriented substantially perpendicular to the surface of the non-magnetic substrate 1 and has a pseudo-hexagonal structure.
1. A magnetic recording medium comprising:
at least an underlayer, an orientation control layer, a magnetic recording layer, and a protective layer formed on a non-magnetic substrate,
wherein the orientation control layer has a multi-layer structure including at least a seed layer and an intermediate layer,
the seed layer is arranged closer to the non-magnetic substrate than the intermediate layer,
the seed layer includes an alloy layer that is made of a Cu—Ti alloy, which is a main material, having Cu as a main component, and in the Cu—Ti alloy, the content of Cu is in the range of 85 at % to 95 at %, and the content of Ti is in the range of 5 at % to 15 at %,
the Cu—Ti alloy has a (111) crystal plane oriented substantially perpendicular to the surface of the non-magnetic substrate and has a pseudo-hexagonal structure,
a film thickness of the seed layer is equal to or greater than 3 nm and equal to or less than 10 nm,
the seed layer is formed directly on the soft magnetic underlayer, and
the soft magnetic underlayer has a soft magnetic amorphous structure.
2. The magnetic recording medium according to claim 1 ,
wherein the intermediate layer includes a metal layer that is made of Ru, Re, or any one of alloy materials thereof, which is a main material, and has a hexagonal close-packed structure.
3. The magnetic recording medium according to claim 1 ,
wherein the intermediate layer has at least one element selected from elements having a face-centered cubic structure as a main component, an alloy containing an element having a body-centered cubic structure, a face-centered cubic structure performing (111) crystal plane orientation approximately perpendicularly to the surface of the non-magnetic substrate, and an irregular layer lattice being in layers and a body-centered cubic structure therein.
4. The magnetic recording medium according to claim 1 ,
wherein the intermediate layer has at least one element selected from elements having a face-centered cubic structure as a main component, an alloy containing an element having a hexagonal close-packed structure, a face-centered cubic structure performing (111) crystal plane orientation approximately perpendicularly to the surface of the non-magnetic substrate, and an irregular layer lattice being in layers and a hexagonal close-packed structure therein.
5. The magnetic recording medium according to claim 1 ,
wherein the magnetic recording layer includes a magnetic layer that has a granular structure formed by ferromagnetic crystal particles and a grain boundary made of a non-magnetic oxide, and
the average diameter of the ferromagnetic crystal particles in the magnetic layer is equal to or less than 7.5 nm in particle diameter analysis using a transmission electron microscope.
6. A magnetic recording/reproducing apparatus comprising:
the magnetic recording medium according to claim 1 ; and
a magnetic head that records or reproduces information on or from the magnetic recording medium.