Self‐Bias Response of Lead‐Free (1− x )[0.948 K 0.5 Na 0.5 NbO 3 –0.052 LiSbO 3 ]– x Ni 0.8 Zn 0.2 Fe 2 O 4 –Nickel Magnetoelectric Laminate Composites

This study reports the magnetoelectric (ME) response of lead‐free particulate composites given as (1− x )[0.948 K 0.5 Na 0.5 NbO 3 –0.052 LiSbO 3 ]– x Ni 0.8 Zn 0.2 Fe 2 O 4 (KNNLS–NZF) and bimorph laminates given as KNNLS–NZF/Ni/KNNLS–NZF. The particulate ME composites were found to exhibit island–matrix microstructure as confirmed by scanning electron microscopy and elemental mapping. Detailed investigations were conducted on optimization of the magnitude of magnetic and piezoelectric properties by varying the sintering condition and NZF mole fraction. It was found that longitudinal piezoelectric strain coefficient d 33 and electromechanical coupling factor k p decreased with increasing NZF concentration. On the other hand, the magnitude of saturation magnetization M s , remnant magnetization M r , magnetic permeability μ, and magnetostriction λ was found to increase with increasing NZF fraction. The composition 0.7 KNNLS–0.3 NZF sintered at 1060°C was found to exhibit d 33 of 73 pC/N, M s of 19 emu/g, and maximum ME coefficient α E of 20.14 mV/cm·Oe under H ac =1 Oe at 1 kHz. The bimorph laminates were fabricated by embedding Ni plate between (1− x )KNNLS– x NZF disks with varying electrical connections to achieve radial and bending modes. The radial mode laminates were found to exhibit typical ME response without any self‐bias effect with maximum α E of 261.3 mV/cm·Oe and high DC magnetic field sensitivity of 1 μT at 1 kHz. The bending mode laminates were found to exhibit self‐biased ME response whose magnitude and shape was dependent upon the NZF concentration.