Sreenivasulu, GollapudiQu, PengPetrov, Vladimir M.Qu, HongweiSrinivasan, Gopalan2017-09-202017-09-202016-02-20Sreenivasulu, G.; Qu, P.; Petrov, V.; Qu, H.; Srinivasan, G. Sensitivity Enhancement in Magnetic Sensors Based on Ferroelectric-Bimorphs and Multiferroic Composites. Sensors 2016, 16, 262.http://hdl.handle.net/10919/79273Multiferroic composites with ferromagnetic and ferroelectric phases have been studied in recent years for use as sensors of AC and DC magnetic fields. Their operation is based on magneto-electric (ME) coupling between the electric and magnetic subsystems and is mediated by mechanical strain. Such sensors for AC magnetic fields require a bias magnetic field to achieve pT-sensitivity. Novel magnetic sensors with a permanent magnet proof mass, either on a ferroelectric bimorph or a ferromagnetic-ferroelectric composite, are discussed. In both types, the interaction between the applied AC magnetic field and remnant magnetization of the magnet results in a mechanical strain and a voltage response in the ferroelectric. Our studies have been performed on sensors with a Nd-Fe-B permanent magnet proof mass on (i) a bimorph of oppositely-poled lead zirconate titanate (PZT) platelets and (ii) a layered multiferroic composite of PZT-Metglas-Ni. The sensors have been characterized in terms of sensitivity and equivalent magnetic noise N. Noise N in both type of sensors is on the order of 200 pT/√Hz at 1 Hz, a factor of 10 improvement compared to multiferroic sensors without a proof mass. When the AC magnetic field is applied at the bending resonance for the bimorph, the measured N ≈ 700 pT/√Hz. We discuss models based on magneto-electro-mechanical coupling at low frequency and bending resonance in the sensors and theoretical estimates of ME voltage coefficients are in very good agreement with the data.application/pdfenCreative Commons Attribution 4.0 Internationalmagnetic sensorpiezoelectricferroelectricmultiferroicbimorphbending resonanceproof masspermanent magnetSensitivity Enhancement in Magnetic Sensors Based on Ferroelectric-Bimorphs and Multiferroic CompositesArticle - Refereed2017-09-20Sensorshttps://doi.org/10.3390/s16020262