Negative thermal expansion property of Sm1−xCuxMnO3−δ

Abstract

The negative thermal expansion (NTE) property of a Sm1−xCuxMnO3−δ (x = 0.05, 0.1, 0.15, 0.2) material was studied in detail. The Sm1−xCuxMnO3−δ was synthesized by a solid phase method. The SEM, EDS, XRD, and XPS results indicate that Sm1−xCuxMnO3−δ crystallizes in an orthorhombic symmetry structure with polyhedron grains. Sm0.85Cu0.15MnO3−δ exhibits NTE property from 473 K to 873 K with the liner coefficient of thermal expansion (CTE) −5.93 × 10−6/K. We analyzed that the additive of Cu2+ enhance the extent of distortion in perovskite structure, which play an important role in the thermal expansion property. It is indicated that the lattice distortion, Pore size and oxygen vacancy provide an essential condition for NTE in this material.

Keywords

• Negative thermal expansion
• Sm1−xCuxMnO3−δ
• Expansion coefficient
• Jahn–Teller effect
• Oxygen vacancy
• Pore size