BiFeO3–CoFe2O4–PbTiO3 composites: structural, multiferroic, and optical characteristics

Abstract

Three-phase magnetoelectric composites (1 -x) (0.7BiFeO 3 -0.3CoFe 2 O 4 )-xPbTiO 3 (or equivalently written as (1 -x)(0.7BFO-0.3CFO)-xPT) with x variations 0, 0.30, 0.35, 0.40, 0.45, and 1.0 were synthesized using hybrid processing route. The effects of PT addition on structural, multiferroic, and optical properties have been subsequently investigated. A detailed Rietveld refinement analysis of X-ray diffraction patterns has been performed, which confirms the presence of structural phases of individual constituents in the composites. Field emission scanning electron microscopy images are taken for microstructural analysis and grain size determination. Transmission electron microscopy analysis of 0.3CFO-0.7BFO reveals the average particle size to be lying in the window of 10-15 nm. The temperature-dependent dielectric constant at various frequencies (1, 10, 50, 100, and 500 kHz) has been studied, and the dielectric study reveals the increase of dielectric constant and decrease of average dielectric loss of composites with incorporation of PT content. Room temperature ferromagnetic behavior of composites is confirmed through the observation of magnetization versus magnetic field (M-H) hysteresis loops. The variation of magnetization with temperature indicates the presence of spin glass behavior in composites. Magnetoelectric coupling is evidenced in the composites through the observation of dependence of the dielectric constant on magnetic field, and magnetodielectric response of 2.05 % is observed for 45 mol% addition of PT content. The fractional change of magnetic field-induced dielectric constant can also be expressed as De r * cM 2 , and the value of c is found to be *1.08 9 10 -2 (emu/g) -2 for composite with x = 0.40. Fourier transformed infrared spectroscopy of samples is carried out to analyze various bonds formation in the composites.

Study of band structure, transport and magnetic properties of BiFeO3–TbMnO3 composite

“…The presence of TbMnO 3 perovskite phase in the composite is confirmed by identifying the stretching vibration of Mn-O-Mn bond ~ 573 cm −1 arising from MnO 6 octahedra of the compound (denoted as C in the spectrum). Apart from these bands few other bands can be identified in the spectrum such as 1720 cm −1 assigned to the bending vibrations of H 2 O which arises due to the presence of moistures in the powder [33,35]. The bands ~ 1070 cm −1 and 1440 cm −1 are ascribed to the stretching vibrations of C=O and C-C, respectively, which appears due to the absorption of carbon during the exposure of the sample to air [36].…”

Multiferroic BiFe1−xTMxO3/NiFe2O4 (TM = Mn, Cr) thin films: Structural, electrical and magnetic properties

“…It is obvious that the polarization current of the BFMO/NFO thin film is higher than the BFMCO/NFO thin film at all the applied electric field, especially near the + E c . [37]. But for the BFMO/NFO and BFMCO/NFO thin films, the better magnetic property of the BFMCO/NFO thin film is attributed to the further destroyed spin cycloid, the spin interaction between Cr and Fe ions [38], the variation in Fe-O-Fe bond length and space group in the crystal structure due to Cr-doping [39].…”

Evidence of magneto-electric coupling and electrical study of CFO modified BNT/BT composites

“…MC effect of ∼2.4% (at 1 T) and ∼1.5% (at 0.5 T) was observed at about 10 kHz frequency. Magneto-dielectric behaviour in the ME composite samples may arise due to several possible reasons, such as magneto-resistance effect, magnetostriction effect, or ME coupling [13].…”

“…(1) where M stands for molecular weight, σ ′ S signifies magnetization value per gram mol of the sample and 5585 is the magnetic factor [13]. Values of M s , M r , coercive field (H c ) and magnetic moments η B of all the composite samples are listed in Table 3.…”