Magnetoresistive element with a Heusler alloy layer that has a region in which an additive element changes in concentration

A thin-film magnetic head comprising:

• a medium facing surface that faces toward a recording medium;
• a magnetoresistive element disposed near the medium facing surface to detect a signal magnetic field sent from the recording medium;
• and a pair of electrodes for feeding a current for detecting magnetic signals to the magnetoresistive element in a direction intersecting a plane of each layer making up the magnetoresistive element, the magnetoresistive element comprising:
• a nonmagnetic conductive layer having a first surface and a second surface that face toward opposite directions;
• a pinned layer disposed adjacent to the first surface of the nonmagnetic conductive layer, a direction of magnetization in the pinned layer being fixed;
• and
• a free layer disposed adjacent to the second surface of the nonmagnetic conductive layer, a direction of magnetization in the free layer changing in response to an external magnetic field, wherein:
• in the magnetoresistive element, the current for detecting magnetic signals is fed in the direction intersecting the plane of each of the foregoing layers;
• the nonmagnetic conductive layer contains an element that is a main component of the nonmagnetic conductive layer;
• at least one of the pinned layer and the free layer includes a Heusler alloy layer;
• the Heusler alloy layer contains a Heusler alloy in which atoms of a magnetic metallic element are respectively placed at body-centered positions of unit cells, and contains an additive element that is a nonmagnetic metallic element that does not constitute the Heusler alloy, the additive element being different from the element that is the main component of the nonmagnetic conductive layer;
• and
• the at least one of the pinned layer and the free layer includes a region in which a concentration of the additive element increases as a distance from the nonmagnetic conductive layer decreases, the region being adjacent to the nonmagnetic conductive layer.

A head gimbal assembly comprising:

• a slider including a thin-film magnetic head and disposed to face toward a recording medium;
• and a suspension flexibly supporting the slider,
• the thin-film magnetic head comprising:
• a medium facing surface that faces toward the recording medium;
• a magnetoresistive element disposed near the medium facing surface to detect a signal magnetic field sent from the recording medium;
• and a pair of electrodes for feeding a current for detecting magnetic signals to the magnetoresistive element in a direction intersecting a plane of each layer making up the magnetoresistive element,
• the magnetoresistive element comprising:
• a nonmagnetic conductive layer having a first surface and a second surface that face toward opposite directions;
• a pinned layer disposed adjacent to the first surface of the nonmagnetic conductive layer, a direction of magnetization in the pinned layer being fixed;
• and
• a free layer disposed adjacent to the second surface of the nonmagnetic conductive layer, a direction of magnetization in the free layer changing in response to an external magnetic field, wherein:
• in the magnetoresistive element, the current for detecting magnetic signals is fed in the direction intersecting the plane of each of the foregoing layers;
• the nonmagnetic conductive layer contains an element that is a main component of the nonmagnetic conductive layer;
• at least one of the pinned layer and the free layer includes a Heusler alloy layer;
• the Heusler alloy layer contains a Heusler alloy in which atoms of a magnetic metallic element are respectively placed at body-centered positions of unit cells, and contains an additive element that is a nonmagnetic metallic element that does not constitute the Heusler alloy, the additive element being different from the element that is the main component of the nonmagnetic conductive layer;
• and
• the at least one of the pinned layer and the free layer includes a region in which a concentration of the additive element increases as a distance from the nonmagnetic conductive layer decreases, the region being adjacent to the nonmagnetic conductive layer.

A head arm assembly comprising:

• a slider including a thin-film magnetic head and disposed to face toward a recording medium;
• a suspension flexibly supporting the slider;
• and an arm for making the slider travel across tracks of the recording medium, the suspension being attached to the arm,
• the thin-film magnetic head comprising:
• a medium facing surface that faces toward the recording medium;
• a magnetoresistive element disposed near the medium facing surface to detect a signal magnetic field sent from the recording medium;
• and a pair of electrodes for feeding a current for detecting magnetic signals to the magnetoresistive element in a direction intersecting a plane of each layer making up the magnetoresistive element,
• the magnetoresistive element comprising:
• a nonmagnetic conductive layer having a first surface and a second surface that face toward opposite directions;
• a pinned layer disposed adjacent to the first surface of the nonmagnetic conductive layer, a direction of magnetization in the pinned layer being fixed;
• and
• a free layer disposed adjacent to the second surface of the nonmagnetic conductive layer, a direction of magnetization in the free layer changing in response to an external magnetic filed, wherein:
• in the magnetoresistive element, the current for detecting magnetic signals is fed in the direction intersecting the plane of each of the foregoing layers;
• the nonmagnetic conductive layer contains an element that is a main component of the nonmagnetic conductive layer;
• at least one of the pinned layer and the free layer includes a Heusler alloy layer;
• the Heusler alloy layer contains a Heusler alloy in which atoms of a magnetic metallic element are respectively placed at body-centered positions of unit cells, and contains an additive element that is a nonmagnetic metallic element that does not constitute the Heusler alloy, the additive element being different from the element that is the main component of the nonmagnetic conductive layer;
• and
• the at least one of the pinned layer and the free layer includes a region in which a concentration of the additive element increases as a distance from the nonmagnetic conductive layer decreases, the region being adjacent to the nonmagnetic conductive layer.

A magnetic disk drive comprising:

• a slider including a thin-film magnetic head and disposed to face toward a recording medium that is driven to rotate;
• and an alignment device supporting the slider and aligning the slider with respect to the recording medium,
• the thin-film magnetic head comprising:
• a medium facing surface that faces toward the recording medium;
• a magnetoresistive element disposed near the medium facing surface to detect a signal magnetic field sent from the recording medium;
• and a pair of electrodes for feeding a current for detecting magnetic signals to the magnetoresistive element in a direction intersecting a plane of each layer making up the magnetoresistive element,
• the magnetoresistive element comprising:
• a nonmagnetic conductive layer having a first surface and a second surface that face toward opposite directions;
• a pinned layer disposed adjacent to the first surface of the nonmagnetic conductive layer, a direction of magnetization in the pinned layer being fixed;
• and
• a free layer disposed adjacent to the second surface of the nonmagnetic conductive layer, a direction of magnetization in the free layer changing in response to an external magnetic field, wherein:
• in the magnetoresistive element, the current for detecting magnetic signals being fed in the direction intersecting the plane of each of the foregoing layers;
• the nonmagnetic conductive layer contains an element that is a main component of the nonmagnetic conductive layer;
• at least one of the pinned layer and the free layer includes a Heusler alloy layer;
• the Heusler alloy layer contains a Heusler alloy in which atoms of a magnetic metallic element are respectively placed at body-centered positions of unit cells, and contains an additive element that is a nonmagnetic metallic element that does not constitute the Heusler alloy, the additive element being different from the element that is the main component of the nonmagnetic conductive layer;
• and
• the at least one of the pinned layer and the free layer includes a region in which a concentration of the additive element increases as a distance from the nonmagnetic conductive layer decreases, the region being adjacent to the nonmagnetic conductive layer.