Generally,most materials expand when heated and contract when cooled,whereas negative thermal expansion(NTE)materials are very rare.As a typical NTE material,PbTiO_(3) and related compounds have drawn particular inter...Generally,most materials expand when heated and contract when cooled,whereas negative thermal expansion(NTE)materials are very rare.As a typical NTE material,PbTiO_(3) and related compounds have drawn particular interest in recent years.The discovery of an enhanced NTE system in PbTiO_(3) is beneficial to deepen our understanding of its mechanism and regulate its properties.At present,the method of discriminating an enhanced NTE material based on PbTiO_(3) is not universal.Here,we propose a semi-empirical method through evaluating the average lattice distortion in related systems to estimate the relative coefficient of thermal expansion conveniently.The rationality of the method was verified by the analysis of the 0.6PbTiO_(3)-0.4Bi(Ga_(x)Fe_(1-x))O_(3) system.So far,all PbTiO_(3)-based compounds with enhanced NTE conform well to this method.This method provides the possibility to find more enhanced NTE PbTiO_(3)-based materials.展开更多
基金financially supported by the National Key R&D Program of China(No.2020YFA0406202)the National Natural Science Foundation of China(Nos.22090042 and 21731001)。
文摘Generally,most materials expand when heated and contract when cooled,whereas negative thermal expansion(NTE)materials are very rare.As a typical NTE material,PbTiO_(3) and related compounds have drawn particular interest in recent years.The discovery of an enhanced NTE system in PbTiO_(3) is beneficial to deepen our understanding of its mechanism and regulate its properties.At present,the method of discriminating an enhanced NTE material based on PbTiO_(3) is not universal.Here,we propose a semi-empirical method through evaluating the average lattice distortion in related systems to estimate the relative coefficient of thermal expansion conveniently.The rationality of the method was verified by the analysis of the 0.6PbTiO_(3)-0.4Bi(Ga_(x)Fe_(1-x))O_(3) system.So far,all PbTiO_(3)-based compounds with enhanced NTE conform well to this method.This method provides the possibility to find more enhanced NTE PbTiO_(3)-based materials.
