Effect of diamagnetic Ca, Sr, Pb, and Ba substitution on the crystal structure and multiferroic properties of the BiFeO3 perovskite

Abstract

International audienceIn this work, we studied the effect of heterovalent Ca, Sr, Pb, and Ba substitution on the crystal structure, dielectric, local ferroelectric, and magnetic properties of the BiFeO3 multiferroic perovskite. Ceramic solid solutions with the general formula Bi0.7A0.3FeO3 (A is a doping element) were prepared and characterized by x-ray diffraction, dielectric, piezoresponse force microscopy (PFM), and magnetic measurements. It is shown that the crystal structure of the compounds is described within the space group R3c, permitting the spontaneous polarization, whose existence was confirmed by the PFM data. Magnetic properties of the solid solutions are determined by the ionic radius of the substituting element. Experimental results suggest that the increase in the radius of the A-site ion leads to the effective suppression of the spiral spin structure of BiFeO3, resulting in the appearance of net magnetization

Phase transition and enhanced magneto-dielectric response in BiFeO3-DyMnO3 multiferroics

“…In the structural transition from rhombohedral to orthorhombic in BiFeO 3 , the parent rhombohedral phase is responsible for spontaneous ferroelectricity; whereas the orthorhombic phase is responsible for appearance of weak ferromagnetism. 30,34 Moreover, the X-ray characterization clearly demonstrates stoichiometric synthesis of the samples. The possibility of extrinsic contribution from the impurity phase Bi 2 Fe 4 O 9 is negligible as the magnetic ordering temperature of Bi 2 Fe 4 O 9 is well below RT.…”

“…The energy dispersive X-ray analysis (EDX) was used to estimate the overall chemical composition of the samples. Transmission electron microscope (TEM) pattern and selected area diffraction pattern (SAED) were recorded using a TEM Techno G 2 30 STwin. The Raman spectra were measured in the back scattering geometry using the 514.5 nm line of an Ar-ion laser in the frequency range 80-800 cm À1 using Renishaw microRaman spectrometer (model-INVIA).…”

“…This implies the uniform distribution of dopants (Dy 3þ and Mn 3þ ) throughout the lattice. [29][30][31] The average crystallite size and lattice strain of (1 À x) BFO-x DMO system for 0.0 x 0.2 as a function of composition are shown in Fig. S1 (see Supplementary Material).…”

Crystal structure and magnetic properties of Bi0.8A0.2FeO3 (A = La, Ca, Sr, Ba) multiferroics using neutron diffraction and Mossbauer spectroscopy

“…There are many reports on successful improvement of the ferromagnetic properties of BFO by doping methods as ionic substitution inhibits the formation of secondary phase and improves the formation of pure BFO and weak ferromagnetism arises due to the DzyaloshinskiiMoriya interaction. [4][5][6]8 In the present study, we consider following points: (i) a simple way to synthesise at normal condition by solid state reaction method.…”

“…4,5 or diamagnetic divalent ions (Ba 2+ , Pb 2+ , Ca 2+ , etc.) at A-site 6 and/or transition metal ion (Ti 4+ , Mn 3+ etc.) at B-site; 3,7 (ii) fabrication of the high quality single crystal of BiFeO 3 to remove the non-stoichiometric problems; 8 (iii) Synthesis of BiFeO 3 nano-particles having grain size below 62 nm so that spiral spin structure is destroyed that leads to ferromagnetism; 9 (iv) Preparation of solid solutions of BFO with some other perovskites.…”