Enhanced magnetic and ferroelectric properties of K-Hf substituted BiFeO3 multiferroics for magnetoelectric data storage applications

Enhanced magnetic and ferroelectric properties have been observed in Hf substituted Bi0.97K0.9Fe1- (x) Hf-(3/4) (x) O-3 (0.00 <= x <= 0.20) nanocrystalline multiferroics which were synthesized via auto combustion sol-gel method. Citric acid was used as a solvent. Structural investigation confirmed the development of pure perovskite rhombohedral distorted phase. The enlargement in cell volume was observed with K-Hf substitution due to lattice distortion and the ionic radii of substituents. Ferroelectric loops showed that maximum polarization (P (max)) was inclined from 0.000376 to 0.391 mu c/cm(2) as well as remanent polarization (Pr) from 1.000815 to 5.39 mu c/cm(2). This was due to Hf-K contents which altered Fe-O bond length and increase disturbance in FeO6 octahedra which increase polarization. High values of saturation magnetization (Ms = 4.79 emu/g) and remanent magnetization (Mr = 1.7 emu/g) was attributed to disturbance in antiferromagnetic spin modulated cycloid (lambda = 62 nm) structure. Enhancements of magnetic properties along with the formation of P-E loops make these multiferroic nanomaterials the best candidates for magnetoelectric RAMS.