Structural, magnetic and ferroelectric properties of lead free piezoelectric 0.9(0.45Ba(0.7)Ca(0.3)TiO(3)-0.55BaTi(0.8)Zr(0.2)O(3)) and magnetostrictive 0.1(Co0.7Mn0.3Fe1.95Dy0.05O4) magnetoelectric particulate composite

Abstract

The structural, magnetic, ferroelectric, and magnetoelectric (ME) properties of lead-free ferroelectric phase (0.45)Ba0.7Ca0.3TiO3-(0.55)BaTi0.8Zr0.2O3 (BCZT) and rare earth modified Co-Mn ferrite phase Co0.7Mn0.3Fe1.95Dy0.05O4 (CMFDO) magnetoelectric (ME) composites are reported. X-ray diffraction confirms the presence of a crystal structure corresponding to both the ferroelectric and ferrite phases, which was further confirmed by Raman spectroscopic measurements. Scanning electron micrograph imaging along with the elemental mapping reveals the distribution of CMFDO grains in a BCZT matrix. The variation of dc resistivity with temperature indicates a semiconducting nature of the ME composite. The ME composite shows usual dielectric dispersion behavior with a higher dielectric constant value in the low frequency region compared to the individual ferroic phases, due to the space charge effects. Frequency dependent ac conductivity reveals that the conduction process in the ME composite is due to the small polaron hopping mechanism. Also, the variation of dielectric constant with temperature reveals the presence of two dielectric anomalies corresponding to ferroelectric phase transitions, i.e., from orthorhombic (O) to tetragonal (T) phases (∼298–323 K) and tetragonal (T) to cubic (C) phases (∼400 K). The ME composite exhibits both the ferroelectric [i.e., polarization (P) vs electric field (E)] and ferrimagnetic [i.e., magnetization (M) vs magnetic field (H)] hysteresis loops that confirm its multiferroic nature. The P-E hysteresis loop indicates the significant changes in remanent polarization (ΔPr ∼ 54%) after magnetic poling, confirming the presence of strong magnetoelectric coupling in the ME composite. Further, the strength of the ME coupling calculated was ∼54%, which is remarkable. Thus, the ME composite prepared in the present study may be a suitable candidate for applications in magnetic field sensors and multistate memory devices and may be suitable alternatives for single phase multiferroics