Effects of octahedral thickness variance on the temperature coefficient of resonant frequency of the B -site deficient hexagonal perovskites

The temperature coefficient of resonant frequency ( τ f ) and the structure of B -site deficient hexagonal perovskite materials have been assembled with the intention of understanding the structure-property relationship. Based on the refined structure data, the authors proposed a structure-related parameter v to characterize the octahedral thickness variance. Therefore, a correlation between the value of τ f and the octahedral thickness variance has been established. This approach illustrates that the octahedral thickness variance plays an important role in the value and sign of τ f . It also gives a satisfying explanation for the variation of τ f in the Ba 5 Nb 4 O 15 - Ba 5 Ta 4 O 15 system.