Piezoelectrically actuated magnetic-field sensor

A magnetic-field sensor configured to provide an output signal in response to an external magnetic field, comprising:

• a substrate having a surface, wherein the substrate includes at least one cavity defined by an edge on the surface;
• and
• two instances of a modulation sensor, wherein a given modulation sensor includes:
• a pair of cantilevers, separated by a gap, disposed over the cavity, wherein a given cantilever includes a structural layer, a bottom electrode, a piezoelectric layer disposed on the bottom electrode, and a magnetic-flux concentrator disposed on the piezoelectric layer, and wherein the magnetic-flux concentrator is configured to guide the external magnetic field to the gap;
• a magnetoresistive sensor, disposed in the gap, configured to provide the output signal in response to the external magnetic field;
• and
• connectors electrically coupled to the bottom electrodes and the magnetic-flux concentrators in the pair of cantilevers, wherein the connectors are configured to apply voltages having a fundamental frequency across the piezoelectric layers in the pair of cantilevers;
• wherein, in response to the applied voltages, the pair of cantilevers is configured to displace, at the fundamental frequency, relative to the magnetoresistive sensor along a direction perpendicular to the surface;
• and
• wherein the magnetic-field sensor is configured to provide the output signal based on the measurement signals from the magnetoresistive sensors in the two instances of the modulation sensor.

A method for providing an output signal in response to an external magnetic field, wherein the method comprises:

• conveying the external magnetic field using magnetic-flux concentrators in a pair of cantilevers to a gap between the pair of cantilevers, wherein a given cantilever includes a structural layer, a bottom electrode, a piezoelectric layer disposed on the bottom electrode, and one of the magnetic-flux concentrators, and wherein the pair of cantilevers is disposed over a cavity having an edge defined in a surface of a substrate;
• applying a voltage having a fundamental frequency across the piezoelectric layers in the pair of cantilevers in order to displace the pair of cantilevers, at the fundamental frequency, relative to a magnetoresistive sensor disposed in the gap and along a direction perpendicular to the surface;
• and
• transforming the external magnetic field into an output signal using the magnetoresistive sensor.