Effect of Ho Doping on Structure and Ferroelectric Property of Bi_(4-x)Ho_xTi_3O_(12) Ceramics

Ho-doped bismuth titanate(Bi4-xHoxTi3O12) ceramics were prepared by hot-press sintering.The effects of Ho doping on the crystalline phase,density,microstructure and ferroelectric property of the ceramics were investigated.At first,Bi4-xHoxTi3O12(x=0 0.8) powders in the main phase of Bi4Ti3O12 were synthesized from Bi2O3,TiO2 and Ho2O3 micro-powders by solid-state reaction at 900℃.The as-synthesized powders were then sintered by hot-press at 850℃ and 30 MPa to prepare Bi4-xHoxTi3O12 ceramics.With the appropriate Ho doping content of x=0 0.4,single-phased and dense(relative density 99%) Bi4-xHoxTi3O12 ceramics were obtained.The remanent polarization(Pr) of the ceramics increased with Ho doping increasing but decreased at x0.4,mainly due to the oxygen vacancy concentration and different doping sites.The Bi4-xHoxTi3O12 ceramics have the highest value of 2Pr=13.92 μC/cm2 at x=0.4,which is higher that that of the undoped Bi4Ti3O12 ceramics.The result indicates that appropriate Ho doping can improve the ferroelectric property of Bi4Ti3O12ceramics.