Linear sensor with dual spin valve element having reference layers with magnetization directions different from an external magnetic field direction

A linear sensor comprising:

• a first bridge comprising:
• a first spin valve;
• a second spin valve in series with the first spin valve;
• a third spin valve in parallel with the first spin valve;
• and
• a fourth spin valve in series with the third spin valve;
• and
• a second bridge comprising:
• a fifth spin valve;
• a sixth spin valve in series with the fifth spin valve element;
• a seventh spin valve in parallel with the fifth spin valve;
• and
• an eighth spin valve in series with the seventh spin valve,
• wherein the first spin valve comprises:
• a first set of reference layers having a magnetization direction in a first direction;
• a first set of free layers having a magnetization direction in a second direction orthogonal to the first direction;
• and
• wherein the fifth spin valve is positioned on the first spin valve,
• wherein the fifth spin valve comprises:
• a second set of reference layers having a magnetization direction in the first direction;
• a second set of free layers having a magnetization direction in a third direction orthogonal to the first direction and antiparallel to the second direction,
• wherein the first direction is neither parallel nor antiparallel to a direction of an external magnetic field,
• wherein the first and second bridges detect magnetic field changes caused by a target object enabling the linear sensor to provide a differential signal indicating a linear position of the target object.