Magnetic and dielectric properties of Ca-substituted BiFeO₃nanoferrites by the sol-gel method

Abstract

Background: A multiferroic material can simultaneously show two or more basic magnetic properties, including ferromagnetism, antiferromagnetism, and ferroelectricity. BiFeO 3 is a multiferroic material with a rhombohedral distorted perovskite structure. Doping can reduce the volatility of Bi and greatly improve the magnetoelectric properties of BiFeO 3 . Methods: To investigate the influence of the doping content we used the following analytical methods: X-ray powder diffraction (XRD), scanning electron microscopy (SEM), microwave network analysis (PNA-N5244A), and the Superconducting Quantum Interference Device (Quantum Design MPMS) test. Results: With the increase of Ca 2+ concentration in the solution, the grain size of Bi 1-x Ca x FeO 3 becomes smaller, showing the role of Ca 2+ ions as the dopant for fine grains. The calcination temperatures are the major causes for the saturated magnetization. The residual magnetization (M r ) and the coercive force (H c ) decrease linearly with the increase of x value, and due to the effect of Ca 2+ substitution at Bi 3+ sites, which causes the valence change of Fe and/or the oxygen vacancies. Conclusions:The XRD result indicates that the diffraction peak emerges with the increase of Ca 2+ and the main diffraction peak achieves a high angle. The best calcining temperature is 600 °C, and the morphology is very dependent on the calcining temperature.

Artificial Intelligence in Repairing Meniscus Injury in Football Sports with Perovskite Nanobiomaterials

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Modification in Structural, Morphological, Magnetic and Ferroelectric Properties of Calcium-Doped Bismuth Ferrite Nanoparticles

“…During conventional processing of this material, it is difficult to obtain larger magnetoelectrics due to the volatilization of A-site Bi , as the existence of the pure phase of BiFeO3 delays the conversion of Fe 3+ into Fe 2+ . This may be due to the presence of an oxygen vacancy, which is the cause of leakage current (Lin et al, 2018).…”

Influência da adição de Ca nas propriedades térmicas e elétricas do BiFeO>sub<3>/sub<

“…Alguns destes mostram que o BFO pode ser utilizado como sensor para gases [7,8], em dispositivos fotovoltaicos [9,10] ou como cátodos em células a combustível de óxido sólido, SOFC [5,6]. Entretanto, o maior destaque é para aplicações magnoeléticas e na spintrônica [11,12].…”

“…Para contornar essas dificuldades, os estudos se concentraram em diferentes métodos de obtenção ou síntese, sendo os mais utilizados atualmente o sol-gel, a co-precipitação e o método hidrotermal [9]. Os métodos químicos mais utilizados para a obtenção do BFO, porém, são processos complexos e que geram maior custo, devido ao tempo utilizado e as etapas envolvidas, quando comparadas com o método convencional de reação em estado sólido.…”