Patent ID: 6640652
Filing Date: 2003-11-04
Classification: G01D

Abstract:
A rotation angle sensor comprising: a fixed part on which giant magnetoresistive elements are provided, each of the giant magnetoresistive elements having a multilayer body including a fixed magnetic layer with a fixed direction of magnetization, a non-magnetic conductive layer, and a free magnetic layer facing said fixed magnetic layer with said non-magnetic conductive layer held between them, and electrode layers connected both ends of said multilayer body; and a rotating part which forms a magnetic field and rotates facing said fixed part,wherein said giant magnetoresistive elements with their fixed magnetic layers having opposite directions of magnetization are provided as a pair on a surface of said fixed part, and said giant magnetoresistive elements as a pair are connected so that a difference between their resistance values is outputted, thus detecting a magnetic field component parallel to the surface of said fixed part provided from said rotating part to said giant magnetoresistive elements, wherein the size of said multilayer body of said giant magnetoresistive element is 1 mm or smaller, and when the shape anisotropy energy (H) of said free magnetic layer is expressed by H=A*Js*(Br/&pgr;), where Js represents saturation magnetization of a magnetic material forming said free magnetic layer and Br represents remanent magnetic flux density of the magnetic material forming said free magnetic layer, âˆ’350