Influence of molar ratio on dielectric, ferroelectric and magnetic properties of Co0.5Mg0.5Fe2O4/Ba0.85Sr0.15TiO3 composite ceramics

Abstract

In the present work, Co 0.5 Mg 0.5 Fe 2 O 4 /Ba 0.85 Sr 0.15 TiO 3 (CMFO/BST) composite ceramics with different molar ratios (1:1, 1:2, 1:4, 1:6 and 1:8) were prepared by sol-gel method and sintered at 1150°C. The effects of molar ratio on the structure, dielectric and multiferroic properties were comparatively studied. The results indicate that all the synthesized composites mainly show bi-phase structure except slight presence of impurity phases. The surface of the specimens is relatively dense and the mean grain size is about 2 µm. It decreases at first and then increases with the increased molar ratio. The dielectric constant shows decreased trend with increasing the molar ratio, while the dielectric loss presents the opposite behaviour. With the increase of molar ratio, the height of the relaxation peak decreases while the peak position shifts to higher temperature range. The relaxation peak evolves gradually from one to two peaks. The residual polarization increases with voltage but decreases with frequency. The maximal polarization of 1.28 µC/cm 2 is obtained in the specimen with the molar ratio of 1:8, due to the largest concentration of ferroelectric phase BST. The magnetization shows abnormal behaviour with the change in molar ratio. The largest saturation and remnant magnetization are 20.89 and 12.66 emu/g, respectively when the molar ratio is 1:2 due to the stronger interface interaction effect between the two phases.

Magnetoelectric properties of materials based on barium zirconium titanate and various magnetic compounds

“…Typical hysteresis loops for ferroelectric materials were obtained for the pure BT80Zr20 ceramics. In the composites, the addition of ferromagnetic phase with higher conductivity influences the ferroelectric order in the materials, therefore the shape of these curves differs from the conventional ferroelectric materials and it is obviously influenced by the properties of magnetic phase [50]. Since the obtained loops are not well saturated it is very difficult to determine remnant polarization and coercive field with high accuracy.…”

Structure, dielectric, magnetic and magnetoelectric coupling properties of xPbTiO3/(1-x)NiFe2O4 composite ceramics

“…Multiferroic materials refer to materials with two or more orders of ferroelectric (antiferroelectric), ferromagnetic (antiferromagnetic) and ferroelastic [1][2][3]. Due to its unique ME coupling properties, multiferroic materials have some special physical properties, some meaningful and new physical phenomena are initiated [2,4].…”

“…Composite multiferroic materials take advantage of the ME coupling between two or more single-phase compounds without multiferroic properties, thus, the composite material with a good ME coupling effect is Z. Zeng et al / Processing and Application of Ceramics 14 [3] (2020) 223-230 formed. It was found that the ME coupling coefficient of composite materials was several times higher than that of single-phase materials [14][15][16].…”