Magnetic sensor and biomagnetism measurement system

摘要

A magnetic sensor includes a plurality of assemblies combined. Each assembly includes a plurality of tunnel magnetoresistive elements, a capacitor and a fixed resistor. The tunnel magnetoresistive dements are (i) disposed in such a way that fixed magnetization directions of fixed magnetic layers are substantially identical and changeable magnetization directions of free magnetic layers with no magnetic field applied are substantially identical and (ii) connected to each other in series-parallel. The capacitor is connected in parallel to the tunnel magnetoresistive elements. The fixed resistor is connected in series to the tunnel magnetoresistive elements and to the capacitor. The assemblies are (i) disposed in such a way that the fixed magnetization directions of the fixed magnetic layers of the assemblies have a relative angle of more than 90 degrees and (ii) connected to each other in series and/or in parallel.

主权项

1. A magnetic sensor comprising a plurality of assemblies combined, each of the assemblies including a plurality of tunnel magnetoresistive elements each (i) including: a fixed magnetic layer having a fixed magnetization direction; a free magnetic layer having a changeable magnetization direction which changes by influence of a magnetic flux from outside; and an insulating layer disposed between the fixed magnetic layer and the free magnetic layer and (ii) changing a current flowing from the fixed magnetic layer to the free magnetic layer depending on an angular difference between the magnetization direction of the fixed magnetic layer and the magnetization direction of the free magnetic layer, wherein
the assembly includes: the tunnel magnetoresistive elements (i) disposed in such a way that the magnetization directions of the fixed magnetic layers are substantially identical and the magnetization directions of the free magnetic layers with no magnetic field applied are substantially identical and (ii) connected to each other in series-parallel; a capacitor connected in parallel to the tunnel magnetoresistive elements which are connected to each other in series-parallel; and a fixed resistor connected in series to the tunnel magnetoresistive elements which are connected to each other in series-parallel and to the capacitor, and the assemblies are (i) disposed in such a way that the magnetization directions of the fixed magnetic layers of the assemblies have a relative angle of more than 90 degrees and (ii) connected to each other in series and/or in parallel.