Magnetoelectric effect in layered ferrite/PZT composites. Study of the demagnetizing effect on the magnetoelectric behavior

V. Loyau, V. Morin, G. Chaplier, M. LoBue, F. Mazaleyrat
2015 Journal of Applied Physics  
We report the use of high magnetomechanical coupling ferrites in magnetoelectric (ME) layered composites. Bilayer samples combining (Ni_0.973 Co_0.027)_1-x Zn_x Fe_2 O_4 ferrites (x = 0-0.5) synthesized by non conventional reactive Spark Plasma Sintering and commercial lead zirconate titanate (PZT) were characterized in term of ME voltage coefficients measured at sub-resonant frequency. Strong ME effects are obtained and we show that an annealing at 1000^∘C and a quenching in air improve the
more » ... zomagnetic behavior of Zn-rich compositions. A theoretical model that predicts the ME behavior was developed, focusing our work on the demagnetizing effects in the transversal mode as well as the longitudinal mode. The model shows that: (i) high ME coefficients are obtained when ferrites with high magnetomechanical coupling are used in bilayer ME composites, (ii) the ME behavior in transversal and longitudinal modes is quite similar, and differences in the shapes of the ME curves are mainly due the demagnetizing effects, (iii) in the transversal mode, the magnetic field penetration depends on the ferrite layer thickness and the ME coefficient is affected accordingly. The two later points are confirmed by measurements on ME samples and calculations. Performances of the ME composites made with high magnetomechanical coupling ferrites are compared to those obtained using Terfenol-D materials in the same conditions of size, shape, and volume ratio. It appears that a ferrite with an optimized composition has performances comparable to those obtained with Terfenol-D material. Nevertheless, the fabrication processes of ferrites are quite simpler. Finally, a ferrite/PZT based ME composite was used as a current sensor.
doi:10.1063/1.4919722 fatcat:fe65clfidfer7agyz7d6sz6nf4