Patent ID: 7218484

Claim:
A magnetoresistance effect element comprising: a magnetoresistance effect film including a first ferromagnetic layer whose direction of magnetization is pinned substantially in one direction, a second ferromagnetic layer whose direction of magnetization changes in response to an external magnetic field, and an intermediate layer provided between the first and second ferromagnetic layers; a pair of electrodes electrically coupled to the magnetoresistance effect film and configured to supply a sense current perpendicularly to a film plane of the magnetoresistance effect film; and a phase separation layer provided between the pair of electrodes, the phase separation layer comprising a first phase and a second phase formed by a phase separation in a solid phase from an alloy including a plurality of elements, one of the first and second phases including at least one element selected from the group consisting of oxygen, nitrogen, fluorine and carbon in higher concentration than other of the first and second phases, wherein the alloy includes at least one element selected from the first group consisting of silver, gold, platinum, palladium, iridium, osmium and copper, and at least one element selected from the second group consisting of nickel, iron and cobalt, and in a case where the alloy is expressed by a formula M x (Ni 100−y (Fe 100−z Co z ) y ) 100−x where M denotes the element selected from the first group, the composition x is in a range between 1 atomic % and 50 atomic %, the composition y is in a range between 0 atomic % and 50 atomic %, and the composition z is in a range between 0 atomic % and 100 atomic %, or in a case where the alloy is expressed by a formula M u (Co 100−v (Fe 100−w Ni w ) v ) 100−u where M denotes the element selected from the first group, the composition u is in a range between 1 atomic % and 50% atomic %, the composition v is in a range between 0 atomic % and 50 atomic %, and the composition w is in a range between 0 atomic % and 100 atomic %.