Study the influence of Nd and Co/Cr co-substitutions on structural, electrical and magnetic properties of BiFeO 3 nanoparticles

Abstract Multiferroic BFO nanoparticles of the compositions Bi 1− x Nd x FeO 3 ( x =0.05 and 0.1) and Bi 0.9 Nd 0.1 Fe 0.95 TM 0.05 O 3 (Transition Metals, TM=Co and Cr) have been synthesized by low temperature citric acid assisted auto-combustion route. Subsequently, the co-doping effects on structural, dielectric and ferroelectro-magnetic properties of BFO have been investigated. X-ray diffraction analysis hints phase transformation from rhombohedral to orthorhombic for 10% Nd-substituted BFO. TM addition further modifies structure and co-doped samples possess pseudo-cubic symmetry. Magnetic measurement reveals gradual enhancement in weak ferromagnetic nature with increasing doping. A well-developed magnetic hysteresis loop with high magnetization ( M r ~0.35 emu/g) and coercive field ( H c ~1255 Oe) is observed for Nd–Co co-doped sample, whereas other samples exhibit rarely-observed ‘wasp-waisted’ type loops. Dielectric behavior is improved significantly on doping. Temperature-dependent dielectric constant presents a broad peak in the vicinity of Neel׳s temperature ( T N ) for all the samples, signifying strong magnetoelectric coupling. An increment in T N is also observed as a result of Nd-doping and further on adding TM. Leakage current decreases significantly as a result of reduced oxygen vacancies on substitutions. Therefore, co-substitutions of rare-earth and magnetically active transition ions remarkably enrich electric and magnetic characteristics of BFO, and boost multiferroic feasibility.