Magnetoelectric multiferroicity in a newly derived nanocomposite system of (Y0.97Al0.03FeO3)x((Bi0.5Na0.5)0.94Ba0.06TiO3)(1−x) [x = 0.3, 0.5

Abstract

To derive a new multiferroic nanocomposite, Al-doped YFeO3 and Ba doped Bi0.5Na0.5TiO3 were considered as individual components. (Bi0.5Na0.5)0.94Ba0.06TiO3 was synthesized through sol-gel technique and successfully incorporated during the preparation of Y0.97Al0.03FeO3, where two different stoichiometric ratios (YAFO)0.3(BNBT)0.7 and (YAFO)0.5(BNBT)0.5 were considered. Rietveld refinement of X-ray diffractograms confirmed the desired phase formation without any impurity. Different useful structural parameters were evaluated from Rietveld analysis, which is helpful to explore the magnetoelectric behavior of both composites. FESEM micrographs showed spherical/ellipsoidal particles scattered uniformly obeying Gaussian distribution with an average grain size obtained as ∼45.3 nm for (YAFO)0.3(BNBT)0.7 and ∼47.2 for (YAFO)0.5(BNBT)0.5. EDAX spectra confirmed the absence of impurity elements and uniform distribution of constituent elements was confirmed by EDAX mapping. Thermal variation of magnetic susceptibility from 50 K to 950 K was analyzed to know the presence of different magnetic phases in composites. Analyses of zero field cooled and field cooled magnetization variation, observed as a function of temperature and magnetization vs field loops, recorded by VSM reveal the presence of antiferromagnetism in both composites with a maximum magnetization of 0.85 emu/g for (YAFO)0.3(BNBT)0.7 and 1.12 emu/g for (YAFO)0.5(BNBT)0.5 at room temperature (300 K). Dielectric properties observed as a function of temperature (300–450 K) and frequency (100 Hz to 5 MHz) provided various important information like permittivity, loss factor, ferroelectric to paraelectric transition temperature, etc. Room temperature dielectric strength of ∼240 with a very low loss of ∼5, indicates good dielectric nature of both composites. Direct observation of the ferroelectric loop indicates the presence of better ferroelectricity in (YAFO)0.3(BNBT)0.7 (Pmax – ∼0.029 µc/cm2) compared to (YAFO)0.5(BNBT)0.5 (Pmax – ∼0.018 µc/cm2). Magnetocapacitance coefficient is also higher in (YAFO)0.3(BNBT)0.7(∼6%) compared to (YAFO)0.5(BNBT)0.5(∼4%). All these investigations suggest that (YAFO)0.3(BNBT)0.7 can be considered a potential candidate as type II magnetoelectric multiferroic.