• Meyners, Dirk
• Schmidt, Gerhard
• Quandt, Eckhard
• Mccord, Jeffrey
• Knöchel, Reinhard
• Durdaut, Phillip
• Faupel, Franz
• Spetzler, Benjamin
• Kittmann, Anne
• Zabel, Sebastian
• Höft, Michael
• Gerken, Martina
• Schmalz, Julius
• Reermann, Jens

Abstract

<jats:title>Abstract</jats:title><jats:p>We present a comprehensive study of a magnetic sensor system that benefits from a new technique to substantially increase the magnetoelastic coupling of surface acoustic waves (SAW). The device uses shear horizontal acoustic surface waves that are guided by a fused silica layer with an amorphous magnetostrictive FeCoSiB thin film on top. The velocity of these so-called Love waves follows the magnetoelastically-induced changes of the shear modulus according to the magnetic field present. The SAW sensor is operated in a delay line configuration at approximately 150 MHz and translates the magnetic field to a time delay and a related phase shift. The fundamentals of this sensor concept are motivated by magnetic and mechanical simulations. They are experimentally verified using customized low-noise readout electronics. With an extremely low magnetic noise level of ≈100 pT/<jats:inline-formula><jats:alternatives><jats:tex-math>{{{Hz}}}</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msqrt><mml:mrow><mml:mi>Hz</mml:mi></mml:mrow></mml:msqrt></mml:math></jats:alternatives></jats:inline-formula>, a bandwidth of 50 kHz and a dynamic range of 120 dB, this magnetic field sensor system shows outstanding characteristics. A range of additional measures to further increase the sensitivity are investigated with simulations.</jats:p>

Topics

• impedance spectroscopy
• surface
• amorphous
• phase
• thin film
• simulation