Patent ID: 7414881

Claim:
A magnetization direction control method applied to a synthetic antiferromagnet structure including N ferromagnetic layers (N is an integer equal to or more than three) and (N−1) non-magnetic layers interposed therebetween, for controlling magnetization directions of said N ferromagnetic layers without coupling antiferromagnetic material with said synthetic antiferromagnet structure, said method comprising: (a) applying an external magnetic field to said synthetic antiferromagnet structure to thereby directing magnetizations of said N ferromagnetic layers in the substantially same direction; (b) decreasing said external magnetic field to allow magnetizations of one or some of said N ferromagnetic layers to be reversed, wherein said synthetic antiferromagnet structure is designed so that a magnetization of one of said N ferromagnetic layers is reversed more easily than magnetizations of the remaining ferromagnetic layers, in a state in which magnetizations of said N ferromagnetic layers are directed in the same direction.