US 12,475,923 B2
Magnetic recording medium, magnetic storage apparatus, and method for manufacturing magnetic recording medium
Takayuki Fukushima, Chiba (JP); Takehiro Yamaguchi, Chiba (JP); and Yuki Sato, Chiba (JP)
Assigned to Resonac Hard Disk Corporation, Chiba (JP)
Filed by Resonac Corporation, Tokyo (JP)
Filed on Jul. 24, 2024, as Appl. No. 18/782,557.
Claims priority of application No. 2023-120812 (JP), filed on Jul. 25, 2023.
Prior Publication US 2025/0037739 A1, Jan. 30, 2025
Int. Cl. G11B 5/66 (2006.01); G11B 5/851 (2006.01)
CPC G11B 5/672 (2021.05) [G11B 5/851 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A magnetic recording medium comprising:
a substrate, an underlayer, a first magnetic layer, and a second magnetic layer stacked in this order, wherein:
the first magnetic layer includes magnetic grains having a L10 structure,
the second magnetic layer has a granular structure including magnetic grains having a L10 structure, and a grain boundary portion including hexagonal boron nitride,
a (111) plane of the magnetic grains included in the first magnetic layer is covered with boron nitride at an interface with the second magnetic layer,
the magnetic grains included in the second magnetic layer are epitaxially grown from a (001) plane of the magnetic grains included in the first magnetic layer, and excluding the (111) plane of the magnetic grains included in the first magnetic layer,
the magnetic grains included in the first magnetic layer and the magnetic grains included in the second magnetic layer are columnar crystals penetrating the first magnetic layer and the second magnetic layer, respectively,
the boron nitride covering the (111) plane of the magnetic grains included in the first magnetic layer is hexagonal boron nitride having a (001) plane parallel to the (111) plane,
the hexagonal boron nitride included in the grain boundary portion of the second magnetic layer has a (001) plane surrounding a side surface of the magnetic grains included in the second magnetic layer, and
the hexagonal boron nitride included in the grain boundary portion of the second magnetic layer has a crystal orientation that gradually changes at an interface with the boron nitride at the interface between the first magnetic layer and the second magnetic layer.