Large direct magnetoelectric coupling in lead-free (BaCa)(TiSn)O₃ / Ni-Zn ferrite particulate composites

In the present study, we report a significant magnetoelectric coupling in lead-free (1-x)Ba_0.95Ca_0.05Ti_0.95Sn_0.05O₃ - (x)Ni_0.7Zn_0.3Fe₂O₄ (x = 0.10, 0.15, 0.20, 0.25 and 0.30) particulate composites prepared by solid-state route. Phase purity and crystal structure of the composites were examined by the X-ray diffraction measurement. With the incorporation of the magnetic NZFO phase, a decrease in the tetragonality of the ferroelectric BTCS lattice was confirmed by the full pattern match of the XRD data using Rietveld analysis. FESEM micrographs revealed improved microstructures with the addition of ferrite concentrations in the composites. Simultaneous presence of ferroic orders in the composites was confirmed from the room-temperature P-E and M-H hysteresis loops. Direct magnetoelectric voltage measurement of the composites established the strain-mediated coupling between the BTCS and NZFO phases. Highest RT first-order magnetoelectric voltage coefficient (α/d = 6.24 mV/cm-Oe) of the x = 0.25 composite is attributed to better individual ferroic properties and improved microstructure of this sample.