Recently, investigations have focused on developing lead-free ME materials. BaTiO3
lead-free composites were the first ones investigated by Boomgaard et al. in 1978 and were found to exhibit ME coefficients of 130
Oe. Since that time, few studies have been conducted on lead-free ME composites, as shown in Table 6.9
, mainly because of the poor piezoelectric performance of lead-free materials. This problem still remains, but the emphasis on developing lead-free ME composites has increased due to environmental concerns.