| US 7,397,639 B2 | ||
| Magnetic detecting element provided with free layer having layered-ferri configuration | ||
| Tomohiro Yamashita, Niigaka-ken (Japan); Naoya Hasegawa, Niigaka-ken (Japan); Eiji Umetsu, Niigaka-ken (Japan); Ryo Nakabayashi, Niigaka-ken (Japan); and Akira Takahashi, Niigaka-ken (Japan) | ||
| Assigned to TDK Corporation, Tokyo (Japan) | ||
| Filed on Jul. 28, 2005, as Appl. No. 11/194,090. | ||
| Claims priority of application No. 2004-229740 (JP), filed on Aug. 05, 2004. | ||
| Prior Publication US 2006/0028775 A1, Feb. 09, 2006 | ||
| Int. Cl. G11B 5/39 (2006.01) | ||
| U.S. Cl. 360—324.12 [360/324.11] | 12 Claims |
| 1. A magnetic detecting element having a multi-layer film comprising:
a lower gap layer made up of an insulating material, a seed layer formed on the lower gap layer, a pinned magnetic layer formed
directly on the seed layer, a nonmagnetic material layer formed on the pinned magnetic layer, a free magnetic layer formed
on the nonmagnetic material layer, and a protective layer formed on the free magnetic layer,
wherein the pinned magnetic layer has a layered-ferri configuration including a first pinned magnetic layer and a second pinned
magnetic layer which are made up of a magnetic material and layered with a first nonmagnetic intermediate layer situated therebetween,
the first pinned magnetic layer and the second pinned magnetic layer have positive magnetostriction, and the magnetization
direction of each of the first and second pinned magnetic layers is pinned in a uniaxial direction by its uniaxial anisotropy,
and
first and second electrode layers are formed on both sides of the multi-layer film so that a sensing current flows in a direction
parallel to the film surfaces of the pinned magnetic layer, the nonmagnetic material layer, and the free magnetic layer via
the first and second electrode layers, wherein the free magnetic layer has a layered-ferri configuration in which a first
free magnetic layer and a second free magnetic layer, which comprise a magnetic material, are layered with a second nonmagnetic
intermediate layer situated therebetween, and a magnetic film thickness of the second free magnetic layer in contact with
the nonmagnetic material layer is greater than a magnetic film thickness of the first free magnetic layer,
wherein a ratio between the magnetic film thickness of the first free magnetic layer and the magnetic film thickness of the
second free magnetic layer (the magnetic film thickness of the first free magnetic layer/the magnetic film thickness of the
second free magnetic layer) is between 1/5 and 3/5 inclusive.
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