论文部分内容阅读
It is well known that most materials expand upon heating.However,some negative thermal expansion (NTE) materials have been found in the past two decades.The appearance of NTE materials provides good possibility to effectively control thermal expansion of materials [1-2].Most recently,a big family of NTE compounds has been found in functional materials [1].In the present study,we have systematically studied the NTE in perovskite-type PbTiO3 (PT)-based ferroelectrics.PT behaves a strong NTE over a wide temperature range (RT490 ℃).The NTE control ofPT-based ferroelectrics has been well established by various chemical modifications.