Magnetic recording medium with varying composition ratio and magnetic recording device

A magnetic recording medium, comprising:

• a first magnetic region;
• a second magnetic region;
• and
• a third magnetic region, the second magnetic region being provided between the third magnetic region and the first magnetic region in a first direction from the third magnetic region to the first magnetic region,
• 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 atom concentration in the third magnetic region to a third Co atom concentration in the third magnetic region being higher than the second composition ratio,
• a first distance along the first direction between the second magnetic region and the first magnetic region being longer than a second distance along the first direction between the third magnetic region and the second magnetic region, or the first magnetic region being separated from the second magnetic region and the third magnetic region being in contact with the second magnetic region,
• wherein the magnetic recording medium is a perpendicular magnetization medium.