The Interior Diffusion And Surface Adsorption Of Hydrogen In BaTiO₃ Crystal

With a perovskite structure,BaTiO₃ crystal has been widely used in the production of random access memory?RAM?and components for sensing strain,temperature and electron charge or discharge and ultrasonic probes due to its good ferroelectric and piezoelectric.Besides,the dielectric constant of BaTiO₃ is so high that has always been used to make ceramic capacitors,mechanical and electrical equipment.Considering that multifunctional BaTiO₃ may work in various environments,such as in the air or under the water,where hydrogen atoms exist in abundance,so it is necessary to take the effect of hydrogen atoms to BaTiO₃.into account.In this paper,CASTEP calculation software was utilized to discuss the diffusion process and surface adsorption of hydrogen atoms in BaTiO₃ crystalsThe results show that hydrogen atoms are affected by polarity in the diffusion process,and the diffusion barrier in the polarization direction[001]is larger than the diffusion barrier in the vertical polarization direction[010].There was a barrier to diffusion of hydrogen atoms at the third OBa plane in the direction of vertical polarization,however,no barrier in the polarization direction.The barrier to diffusion in the direction of polarization is lower than that of the unstrained structure after applying 8%of strain direction of polarization uniaxially.What's more,this barrier is higher than the first two barriers,together with the appearance of the potential barrier in the middle of the OBa and the OTi plane after applying the same strain biaxially.In the environment containing hydrogen molecules,hydrogen is present in the form of molecular adsorption on the surface of the BaTiO₃ crystal;while in the environment of hydrogen atoms,in the form of atomic adsorption.Moreover,we have found that in the environment of hydrogen molecules,hydrogen molecules are more easily adsorbed on the surface of BaTiO₃ crystals in a domains.