Magnetic field sensor using acoustically driven ferromagnetic resonance

An acoustically driven ferromagnetic resonance (ADFMR) sensor configured to detect a magnetic field, the sensor comprising:

• a piezoelectric substrate;
• an acoustic drive comprising a first acoustic transducer on the piezoelectric substrate configured to launch an acoustic wave;
• a second acoustic transducer on the piezoelectric substrate configured to receive the acoustic wave;
• a detection circuit coupled to the second acoustic transducer;
• and
• a magnetostrictive ferromagnet on the piezoelectric substrate between the first acoustic transducer and the second acoustic transducer;
• wherein the acoustic drive is configured to generate the acoustic wave to bias the magnetostrictive ferromagnet at or near a ferromagnetic resonance of the magnetostrictive ferromagnet such that ferromagnetic resonance related absorption is greater than 10%, and
• wherein the detection circuit is configured to detect a magnetic field experienced at the magnetostrictive ferromagnet by measuring at least one of magnetic absorption and phase of the acoustic wave received by the second acoustic transducer.

An acoustically driven ferromagnetic resonance (ADFMR) sensor configured to detect a magnetic field, the sensor comprising:

• a piezoelectric substrate;
• an acoustic drive comprising a first acoustic transducer on the piezoelectric substrate configured to launch an acoustic wave;
• a second acoustic transducer on the piezoelectric substrate configured to receive the acoustic wave;
• a detection circuit coupled to the second acoustic transducer;
• and
• a magnetostrictive ferromagnet on the piezoelectric substrate between the first acoustic transducer and the second acoustic transducer;
• wherein the acoustic drive is configured to generate the acoustic wave to bias the magnetostrictive ferromagnet such that ferromagnetic resonance related absorption of the magnetostrictive ferromagnet is greater than 10%, and
• wherein the detection circuit is configured to determine a magnetic field by measuring at least one of attenuation and phase shift of the acoustic wave received by the second acoustic transducer.