Magnetic-field-induced dielectric behaviors and magneto-electrical coupling of multiferroic compounds containing cobalt ferrite/barium calcium titanate composite fibers

Abstract

Multiferroics have broad application prospects in various fields such as multi-layer ceramic capacitors and multifunctional devices owing to their high dielectric constants and coupled magnetic and ferroelectric properties at room temperature. In this study, cobalt ferrite (CFO)/barium calcium titanate (BCT) composite fibers are prepared from BCT and CFO sols by an electrospinning method, and are then oriented by magnetic fields and sintered at high temperatures. The effects of magnetic fields and CFO contents on the nanostructures and magnetoelectric properties of the composites are investigated. Strong coupling between magnetic and ferroelectric properties occurs in CFO/BCT composites with magnetic orientation. More interestingly, the dielectric constants of CFO/BCT composites with magnetic orientation are found to be enhanced (by ∼1.5–3.5 times) as compared with those of BCT and CFO/BCT without magnetic orientation. The boost of dielectric constants of magnetic-field orientated CFO/BCT is attributed to the magneto-electrical coupling between CFO and BCT, where the polar domains of BCT are pinned by the orientated CFO. Therefore, this work not only provides a novel and effective approach in enhancing the dielectric constants of ceramic ferroelectrics, which is of tremendous value for industrial applications, but also elucidates the interaction mechanisms between ferromagnetic phase and ferroelectric phase in multiferroic compounds.

Qualitative Analysis of Magnetic Moment in BaxTiO3 - Ni xFe3- xO4 Nanocomposite Synthesized by Novel low Temperature Technique

“…It divulges the multiple crystallites or agglomerations in a single particle and form grains, which are separated by crystallographic grain boundaries inside the grains. A much Dissimilarities between crystallite size (from XRD analysis) and grain size (from SEM analysis) has been reported by another set of researchers [1], [2]. It is stated that these are some typical characteristics of oxide-based materials which are the limitations of the XRD technique.…”

“…Multiferroics was also listed as the only one in top ten "Areas to study" in the field of Material Science in the upcoming years. Today such materials have expanded their properties and are also used for advanced electronic devices [1], [2]. These composites have magneto-electric coupling, which is the ability to control the magnetic phase under the influence of an electric field and vice versa [3].…”

“…It is to be noted that when two different phases coexist with each other as multiferroics, there is a dilution between the electric and magnetic phases. In recent periods different types of Multiferroic composites are reported [1]- [6]. It is to be noted that the preparation techniques play a significant role in achieving the desired properties of the final composite material.…”

Variable Dielectric and Ferroelectric Properties in Size-Controlled Cobalt Ferrite

“…CoFe 2 O 4 nanoparticles (CFNPs) exhibit electric nature because of manifestation of dipoles via transferring of charges among multivalent Fe ions. These CFNPs parade robust structure stability and is vital for device applications [1,[7][8][9].…”

“…The synthesis of CFNP with essential physical characteristics and constituent reactivity play key role in devices. Over the last two decades, different methods like co-precipitation, sol-gel, and auto-combustion have evolved for preparation of CFNPs [1,[7][8][9]. In all these methods, by controlling the mixing extent, homogenoussized particles can be prepared.…”