MATERIAL WITH NEGATIVE OR LOW THERMAL EXPANSION COEFFICIENT AND METHOD FOR PRODUCING SAME

摘要

Disclosed is a material with a negative or low thermal expansion coefficient which is substantially composed of one crystal system. The material with a negative or low thermal expansion coefficient is an oxide represented by the chemical formula: ((R<4+>M<2+>)1-xA<3+>2x)(QO4)3 (wherein R represents at least one tetravalent metal element selected from Zr and Hf; M represents at least one divalent metal element selected from Mg, Ca, Sr, Ba and RA; Q represents at least one hexavalent metal element selected from W and Mo; A represents at least one trivalent metal element selected from Al, Sc, Y, Lu, Ga and In; and 0 < x < 1), and is characterized by being substantially composed of one crystal system.