Structural phase transition and negative thermal expansion in Cu 1.8 Zn 0.2 V 2–x P x O 7 solid solutions

Negative thermal expansion (NTE) is exhibited over the entire x range for Cu 1.8 Zn 0.2 V 2– x P x O 7 . In particular, dilatometric measurements using epoxy resin matrix composites containing the spray-dried powder demonstrated that the thermal expansion suppressive capability was almost unchanged for x ≤ 1.0. With increasing x , the X-ray diffraction peak position moves systematically, but some peaks are extremely broad and/or asymmetric, suggesting disorder in the internal structure. The crystallographic analysis confirmed NTE enhancement by microstructural effects at least for x = 0.2. Preliminary measurements suggest higher resistivity and lower dielectric constant than that of pure vanadate, which is suitable for application to electronic devices.