Negative thermal expansion property of Er0.7Sr0.3NiO3−δ

A new kind of negative thermal expansion (NTE) material of Er0.7Sr0.3NiO3 − δ is synthesized by solid-state method and investigated. It is found that Er0.7Sr0.3NiO3 − δ crystallizes in orthorhombic structure with rod-shaped grains. Ceramic Er0.7Sr0.3NiO3 − δ exhibits NTE coefficient of −39.0×10−6K−1 from 655 to 780 K. The results of X-ray diffraction, temperature dependence of Raman spectroscopy and differential scanning calorimetry (DSC) suggest that the NTE phenomenon relates to its phase transition from orthorhombic to rhombohedral.