Magnetic sensor stack body, method of forming the same, film formation control program, and recording medium

A magnetic sensor stack body comprising, on a substrate, a magnetoresistive element whose electric resistance fluctuates when a bias magnetic field is applied and, on sides of opposed junction wall faces of the magnetoresistive element, field regions including a magnetic layer for applying the bias magnetic field to the element,

• wherein at least an underlayer having a body-centered cubic crystal structure (bcc) is provided on the field region,
• the magnetic layer is formed on the underlayer, and
• the magnetic layer is made of a Co—Pt-based alloy having a hexagonal crystal structure (hcp), has no gaps in the layer, has a (10.0) lattice plane, and a squareness ratio exceeding 0.9 along ABS.

A method of forming a magnetic sensor stack body having, on a substrate, a magnetoresistive element whose electric resistance fluctuates when a bias magnetic field is applied and, in field regions on sides of opposed two junction wall faces of the magnetoresistive element, forming a hard bias stack body for applying a bias magnetic field to the element, comprising at least:

• a step of obliquely forming an underlayer along a direction of the junction wall faces at a film forming angle exceeding 45 degrees and less than 90 degrees from a normal of the substrate;
• and
• a step of forming a magnetic layer on the underlayer at a film forming angle of 0 to 30 degrees from the normal of the substrate.