Electrostrictive and piezoelectric materials, which change their shape in response to external fields, have critical applications in many different contexts, working as a muscle. Nowadays, electromechanical active materials are used in everyday technology as components of cameras or sound transducer as well as advanced systems such as microelectronics, energy harvesting or ultrasound imaging. The most diffused electrostrictive materials are Pb-based compounds such as Pb(Mn1/3Nb2/3)O3 (PMN). Not only they contain lead (Pb), which is highly toxic, but their use has been restricted by the European restriction of hazardous substances directive (RoHS) in 2006. For these reasons, many efforts have been made to find an environmentally friendly alternative as a substitute to current materials.