Evidence of improved ferroelectric phase stabilization in Nd and Sc co-substituted BiFeO3

Polycrystalline BiFeO3 and Bi0.9Nd0.1Fe1- xScxO3 (x = 0, 0.05, and 0.10) multiferroic compounds were prepared using conventional solid-state route. X-ray diffraction studies and Raman measurements indicated that the compounds were crystallized in rhombohedral structure with R3c space group. Weak ferromagnetism was induced due to the suppression of canted spin structure in the substituted compounds. Both remanent magnetization (Mr) and coercive field (Hc) were enhanced in Nd and Sc substituted compounds. Further, Néel temperature TN was decreased from 644 K for BiFeO3 to 550 K for Bi0.9Nd0.1Fe0.9Sc0.1O3 compound due to weakening of magnetic exchange interactions between B-site cations in the substituted compounds. Enhanced and nearly well saturated electrical polarizations were observed in Sc substituted compounds, which are attributed to the strengthening of covalent hybridization between Bi and O ions and reduction in oxygen vacancies. The remnant polarization was enhanced to 12.5-μC/cm2 in Bi0.9Nd0.1Fe0.9Sc0.1O3 compound. Impedance studies revealed that insulating character of substituted compounds is enhanced and electrical relaxations are of non-Debye type