Thermal Expansion, Ferroelectric and Magnetic Properties in (1 − x)PbTiO3−xBi(Ni1/2Ti1/2)O3

A zero thermal expansion and multiferroic compound 0.8PbTiO3−0.2Bi(Ni1/2Ti1/2)O3 was developed by a chemical modification route. The structure studies showed that the tetragonality of (1 − x)PbTiO3−xBi(Ni1/2Ti1/2)O3 was gradually weakened to cubic by introducing the dopant Bi(Ni1/2Ti)1/2O3, and the thermal expansion coefficient changed from −8.81 × 10−6/°C to 8.46 × 10−6/°C in 0.1 ≤ x ≤ 0.3 around a wide temperature range (from RT to about 500 °C). Weak ferromagnetic behavior was observed in the solid solutions, and the superexchange interaction was incorporated to explain its nonmonotonous evolution. Meanwhile, the good piezoelectricity and ferroelectricity were well retained. Further investigations demonstrated that the (1 − x)PbTiO3−xBi(Ni1/2Ti1/2)O3 ceramics possessed good mechanical properties, such as high density and excellent fracture toughness. The improved behaviors make the (1 − x)PbTiO3−xBi(Ni1/2Ti1/2)O3 promising piezoceramics with high thermal stability and mechanical performance. The present work provides a way to design and explore high-performance multiferroic compounds in the synthesis route.