US 12,462,838 B2
Magnetic recording medium and magnetic recording device
Ryo Osamura, Kawasaki Kanagawa (JP); Yuji Nakagawa, Kawasaki Kanagawa (JP); Tomoyuki Maeda, Kawasaki Kanagawa (JP); Masayuki Takagishi, Kunitachi Tokyo (JP); Naoyuki Narita, Funabashi Chiba (JP); and Kosuke Kurihara, Yokohama Kanagawa (JP)
Assigned to Kabushiki Kaisha Toshiba, Tokyo (JP); and Toshiba Electronic Devices & Storage Corporation, Tokyo (JP)
Filed by KABUSHIKI KAISHA TOSHIBA, Tokyo (JP); and TOSHIBA ELECTRONIC DEVICES & STORAGE CORPORATION, Tokyo (JP)
Filed on Feb. 8, 2024, as Appl. No. 18/436,535.
Claims priority of application No. 2023-061877 (JP), filed on Apr. 6, 2023.
Prior Publication US 2024/0339128 A1, Oct. 10, 2024
Int. Cl. G11B 5/66 (2006.01); G11B 5/65 (2006.01)
CPC G11B 5/672 (2021.05) [G11B 5/656 (2013.01); G11B 2220/235 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A magnetic recording medium, comprising:
a first magnetic region;
a second magnetic region;
a third magnetic region;
a fourth magnetic region; and
a fifth magnetic region,
the second magnetic region being provided between the fifth magnetic region and the first magnetic region in a first direction from the fifth magnetic region to the first magnetic region,
the third magnetic region being provided between the fifth magnetic region and the second magnetic region in the first direction,
the fourth magnetic region being provided between the fifth magnetic region and the third magnetic region in the first direction,
a first composition ratio of a first Pt atomic concentration in the first magnetic region to a first Co atomic concentration in the first magnetic region being higher than a second composition ratio of a second Pt atomic concentration in the second magnetic region to a second Co atomic concentration in the second magnetic region,
a third composition ratio of a third Pt atomic concentration in the third magnetic region to a third Co atomic concentration in the third magnetic region being higher than the second composition ratio, and higher than a fourth composition ratio of a fourth Pt atomic concentration in the fourth magnetic region to a fourth Co atomic concentration in the fourth magnetic region, and
a fifth composition ratio of a fifth Pt atomic concentration in the fifth magnetic region to a fifth Co atomic concentration in the fifth magnetic region being higher than the fourth composition ratio.