Appeal No. 2002-1417
Application No. 09/306,484
BACKGROUND
The invention is directed to structure of a magnetic sensor utilizing the giant
magnetoresistive (GMR) effect. Such a sensor is referred to in the pertinent art as a
“spin valve” sensor. According to appellants, the inventive arrangement of layers
provides thermal stability superior to that of prior art structures. Claim 1 is reproduced
below.
1. A spin valve magnetoresistive sensor, comprising:
a free layer having a magnetization which changes in the presence of a
magnetic field;
a synthetic antiferromagnet layer, comprising:
a first ferromagnetic layer comprising a layer of CoFe;
a second ferromagnetic layer comprising a layer of CoFe; and
a first spacer layer of nonmagnetic material positioned between
and directly in contact with the first and second ferromagnetic layers, the first
spacer layer comprising a layer of Ru;
a second spacer layer positioned between and directly in contact with the
first ferromagnetic layer of the synthetic antiferromagnetic layer and the free
layer; and
an antiferromagnetic layer comprising:
a buffer layer positioned directly in contact with the second
ferromagnetic layer of the synthetic antiferromagnetic layer, the buffer layer
selected from the group consisting of NiFe and CoFe; and
an Mn-alloy layer positioned directly in contact with the buffer layer.
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