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

A magnetic sensor stack body comprising, on sides of opposed junction wall surfaces of a magnetoresistive element disposed on a substrate, field regions for applying a bias magnetic field to the element,

• wherein the field region includes first and second magnetic layers having magnetic particles having crystal c-axes,
• the first magnetic layer is disposed adjacent to the junction wall surface in the field region, the crystal c-axes in the first magnetic layer are aligned and oriented along an ABS in a film plane,
• the second magnetic layer is disposed adjacent to the first magnetic layer in the field region, the crystal c-axes direction in the second magnetic layer are distributed at random in a plane,
• the first magnetic layer is made of Co—Pt, Co—Cr—Pt, crystal structure (hcp) selected Cr—Pt, or Fe—Pt, Co—Pt, or an alloy thereof,
• the second magnetic layer is made of Co—Pt, Co—Cr—Pt, or an alloy thereof,
• an underlayer made of Cr, Cr—Mo, Cr—Ti, Nb, Ta, W or an alloy thereof having a body-centered cubic crystal structure (bcc) of them is provided on the field region and the junction wall surface,
• the underlayer has a thickness which is 3 to 8 nm in the field region and is less than 3 nm in the junction wall surface,
• the underlayer has a (110) lattice plane in the field region and is in an amorphous state in which no (110) lattice plane is formed in the junction wall surface, and
• the first magnetic layer is formed on the underlayer and has a cross-sectional shape, on a surface parallel to the ABS, of an approximate parallelogram formed by a pair of sides along the junction wall surface and a pair of sides along a face of the substrate in a region adjacent to the junction wall surface.