Saha, S.; Acharya, S.; Popov, M.; Sauyet, T.; Pfund, J.; Bidthanapally, R.; Jain, M.; Page, M.R.; Srinivasan, G. A Novel Spinel Ferrite-Hexagonal Ferrite Composite for Enhanced Magneto-Electric Coupling in a Bilayer with PZT. Sensors2023, 23, 9815.
Saha, S.; Acharya, S.; Popov, M.; Sauyet, T.; Pfund, J.; Bidthanapally, R.; Jain, M.; Page, M.R.; Srinivasan, G. A Novel Spinel Ferrite-Hexagonal Ferrite Composite for Enhanced Magneto-Electric Coupling in a Bilayer with PZT. Sensors 2023, 23, 9815.
Saha, S.; Acharya, S.; Popov, M.; Sauyet, T.; Pfund, J.; Bidthanapally, R.; Jain, M.; Page, M.R.; Srinivasan, G. A Novel Spinel Ferrite-Hexagonal Ferrite Composite for Enhanced Magneto-Electric Coupling in a Bilayer with PZT. Sensors2023, 23, 9815.
Saha, S.; Acharya, S.; Popov, M.; Sauyet, T.; Pfund, J.; Bidthanapally, R.; Jain, M.; Page, M.R.; Srinivasan, G. A Novel Spinel Ferrite-Hexagonal Ferrite Composite for Enhanced Magneto-Electric Coupling in a Bilayer with PZT. Sensors 2023, 23, 9815.
Abstract
The magnetoelectric effect (ME) is an important strain mediated phenomenon in a ferromagnetic-piezoelectric composite for a variety of sensors and signal processing devices. A bias magnetic field, in general, is essential to realize a strong ME coupling in most composites. Magnetic phases with (i) high magnetostriction for strong piezomagnetic coupling and (ii) large anisotropy field that acts as a built-in bias field are preferred so that miniature, ME composite-based devices can operate without the need for an external magnetic field. We are able to realise such a magnetic phase with a composite of (i) barium hexaferrite (BaM) with high magnetocrystalline anisotropy field and (ii) nickel ferrite (NFO) with high magnetostriction. The BNx composites, with (1-x) wt.% of BaM and x wt.% NFO, for x = 0-100, were prepared. X-ray diffraction analysis shows that the composites did not contain any impurity phases. Scanning electron microscopy images revealed that with an increase in NFO content, hexagonal BaM grains become prominent, leading to a large anisotropy field. The NFO rich composites with x ≥60 show a large magnetostriction value of around -23 ppm, comparable to pure NFO. The anisotropy field HA of the composites, determined from ferromagnetic resonance (FMR) measurements, increased with increasing NFO content and reached a maximum of 12.39 kOe for x= 75. This large in-plane HA acted as a built-in field for strong ME effects under zero external bias in a bilayer with PZT. The BN composite was cut into rectangular platelets and bonded with PZT to form the bilayers. ME voltage coefficient (MEVC) measurements at low frequencies and at mechanical resonance showed strong coupling at zero bias for samples with x ≥33. The highest zero-bias MEVC of ~22 mV/cm Oe was obtained for BN75-PZT bilayers wherein BN75 also has the highest HA. Bilayer of BN41-PZT showed a amximum MEVC ~800 mV/cm Oe at electromechanical resonance at 68.4 kHz. The use of hexaferrite-spinel ferrite composite to achieve strong zero-bias ME coupling in bilayers with PZT is significant for applications related to energy harvesting, sensors, and high frequency devices.
Keywords
Magnetoelectric; ferrite; ferroelectric; magnetic anisotropy
Subject
Physical Sciences, Condensed Matter Physics
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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