where U, V and W are the usual peak shape parameters, IG is a measure of the isotropic size effect, DST = coefficient related to strain. As shown in Table 1, the crystallite size decreases with the increase of substituent
SB269970 HCl concentration up to co-substitution of 15%. This implies the development of lattice strain inside the lattice due to ionic size mismatch between host and substituent cations which lead to local structural disorder and reduces the rate of nucleation resulting in decrease of crystallite size. However, the crystallite size increases when substitution concentration increases beyond 15% of co-substitution due to decrease in overall lattice strain decreases. The lattice constants and corresponding unit cell volume decreases with the increase in the substituent concentration due to smaller radius of substituents than that of host cations, which can be inferred from the shift of the XRD peak towards higher 2θ value as shown in Fig. 2. However, their values increases when co-substitution concentration increases beyond 15% (near MPB) because the orthorhombic phase becomes
dominant and overall lattice strain decrease. The gradual shift in XRD peak indicates that the substituents get substituted in the BFO lattice.
