Structure, ferroelectric, and magnetoelectric properties of bulk PZT–NiFe$_{1.9}$Co$_{0.02}$О$_{4-\delta}$ composites

The phase composition, microstructure, and dielectric, ferroelectric, magnetic, and magnetoelectric properties of bulk ceramic $(1-x)$PZT–$x$NiFe$_{1.9}$Co$_{0.02}$О$_{4-\delta}$ composites with 3–0 connectivity have been studied. Using X-ray diffraction and electron microscopy, it has been established that the ferrimagnetic (spinel- like) and ferroelectric (tetragonal perovskite-like) phases separately exist in the composites of all compositions. The simultaneous existence of ferroelectric and ferrimagnetic properties in the composites is confirmed by measuring their $P(E)$ and $\sigma(B)$ hysteresis loops and studying the temperature dependences of dielectric and magnetic properties. The synthesized composites have high magnetoelectric characteristics: their voltage coefficient at $x$ = 0.4 is 215 mV/A at a frequency of 1 kHz and 130 V/A at an electromechanical resonance frequency of 380 kHz.