Patent ID: 8633555

Claim:
A magnetic sensor, suitable for sensing an external magnetic field, the magnetic sensor comprising: a magnetic tunnel junction (MTJ) device, to sense an out-of-plane (Z axis) component of the external magnetic field perpendicular to the MTJ device, wherein the MTJ device comprises: a pinned magnetic layer, having a pinned magnetization perpendicular to the pinned magnetic layer; a tunnel layer, disposed on the pinned magnetic layer; and a magnetic sensing layer, disposed on the tunnel layer, wherein the property of the magnetic sensing layer is perpendicular magnetic anisotropy, the magnetic sensing layer has a thickness set to be within a range having a superparamagnetic property, the superparamagnetic property is that an out-of-plane (Z:axis) magnetic sensitivity at a perpendicular direction to the magnetic sensing layer is larger than an in-plane (X-axis, Y-axis) magnetic sensitivity, and the magnetic sensing layer senses an out-of-plane (Z-axis) magnetic component of the external magnetic field, perpendicular to the magnetic sensing layer, with the out-of-plane magnetic sensitivity, wherein the pinned magnetic layer, the tunnel layer and the magnetic sensing layer are stacked in a forward sequence or a reverse sequence.