Effect of Doping B_2O_3 on Cell Parameters and Transition Temperature of Ba_(1-x)Sr_xTiO_3 Ceramics

The stability of perovskite structure, cell parameters and phase transition temperature of sintered B2O3-doped Ba1-xSrxTiO3(x = 0 ~1) ceramics were investigated. The results show that, with dopant amount increasing, the perovskite structure is maintained but the cell parameters are changed slightly. The c and a change irregularly, while c/a and cell volume (a2c) monotonously decreases and increases respectively. The trasition temperature of doped Ba1-xSrxTiO3 will rise a little, compared with that of undoped ones. With sintering temperature rising, transition temperature decreases since cell volume contracts due to solutionizing of Ba and Sr (with the same dopant content). But with dopant amount increasing, the transition temperature changes hardly (with the same sintering temperature). It means that B2O3 does affect the cell parameters of Ba1-xSrxTiO3, although the ionic radius of B3+ is very small; B3+ entered and stayed in the cell in interstitial mode, but its solid solubility is very limited.