Oblon, Spivak, McClelland, Maier & Neustadt, P.C.
Magnetoresistance effect film and magnetoresistance effect type head having specified antiferromagnetic promote layer
In a spin valve type magnetoresistance effect film, an antiferromagnetization promote layer is formed on a surface of an antiferromagnetic layer remote from a surface thereof abutting a ferromagnetic layer. The antiferromagnetic layer is made of a compound containing Mn and having a CuAu&#8212;I type regular crystal structure. The antiferromagnetic layer has a characteristic requiring a heat treatment for generating the exchange coupling relative to the ferromagnetic layer. The antiferromagnetic layer after the heat treatment is oriented on the (111) crystal orientation surface. The ratio Lp/La of a lattice constant Lp in the closest packed surface of the antiferromagnetization promote layer relative to a lattice constant La in the (111) crystal orientation surface of the antiferromagnetic layer is in the range of 0.9 to 1.1. Accordingly, the regulating temperature of the antiferromagnetic layer can be lowered so that the exchange coupling to the ferromagnetic layer can be generated at a heat treatment temperature as low as possible (for example, no higher than 250&deg; C.). The thus obtained spin valve film is subjected to only quite small deterioration of spin valve film characteristics (for example, MR ratio).
TDK Corporation
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Yoshihiro Masashi Satoru
Tsuchiya Sano Araki