Abstract High performance lead-free multiferroic composites with strong magnetoelectric coupling effect are desired to replace lead-based ceramics in multifunctional device applications due to increasing environmental issues. We report crystal structure, ferroelectric, magnetic, dielectric and magnetoelectric properties of (1-x)Ba0.85Ca0.15Ti0.90Zr0.10O3-(x)CoFe2O4 (BCTZ-CFO) lead-free composites with x = 0.1, 0.3, 0.5, 0.7 and 0.9 synthesized by chemical solution method. BCTZ power was synthesized by sol-gel method while CFO was prepared by metallo-organic decomposition (MOD) method. The XRD results confirm successful formation of the BCTZ-CFO composites without presence of any impurity phase. At room temperature, the BCTZ-CFO composites show multiferroic behavior characterized by ferroelectric and ferromagnetic hysteresis curves. The composite having 10 wt% of CFO exhibited maximum polarization, remnant polarization and coercive field of Ps ∼ 5.1 µC/cm2, Pr ∼ 1.4 µC/cm2 and Ec ∼ 11.6 kV/cm respectively. The BCTZ-CFO composite with 90 wt% of CFO incorporation exhibits improved ferromagnetic properties with Ms ∼ 32 emu/g, Mr ∼ 11.7 emu/g and Hc ∼ 504 Oe. Mӧssbauer spectra analysis show two sets of six-line hyperfine patterns for BCTZ-CFO composites, indicating the presence of Fe3+ ions in both A and B sites. Increasing BCTZ content was found to decrease the hyperfine field strength at both sites and is consistent with the decreasing magnetic moment observed for the samples. The maximum dielectric constant value e′ ∼ 678 is obtained at 1 MHz for composite with 10 wt% of CFO phase. The results indicate that the BCTZ-CFO composites are potential lead-free room temperature multiferroic systems.

中文翻译：

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(1-x)Ba 0.85 Ca 0.15 Ti 0.90 Zr 0.10 O 3 -(x)CoFe 2 O 4 无铅复合材料的结构、多铁性、介电和磁电性能

摘要 由于环境问题日益严重，需要具有强磁电耦合效应的高性能无铅多铁性复合材料在多功能器件应用中替代铅基陶瓷。我们报告了 (1-x)Ba0.85Ca0.15Ti0.90Zr0.10O3-(x)CoFe2O4 (BCTZ-CFO) 无铅复合材料的晶体结构、铁电、磁性、介电和磁电特性，x = 0.1、0.3、0.5 , 0.7 和 0.9 通过化学溶液法合成。BCTZ粉采用溶胶-凝胶法合成，CFO采用金属有机分解（MOD）法制备。XRD 结果证实了 BCTZ-CFO 复合材料的成功形成，不存在任何杂质相。在室温下，BCTZ-CFO 复合材料表现出以铁电和铁磁磁滞曲线为特征的多铁性行为。具有 10 wt% CFO 的复合材料表现出最大极化、剩余极化和矫顽场分别为 Ps ∼ 5.1 µC/cm2、Pr ∼ 1.4 µC/cm2 和 Ec ∼ 11.6 kV/cm。掺入 90 wt% CFO 的 BCTZ-CFO 复合材料表现出改善的铁磁性能，Ms ~ 32 emu/g、Mr ~ 11.7 emu/g 和 Hc ~ 504 Oe。Mӧssbauer 光谱分析显示 BCTZ-CFO 复合材料的两组六线超精细图案，表明在 A 和 B 位点都存在 Fe3+ 离子。发现增加 BCTZ 含量会降低两个位置的超精细场强，并且与观察到的样品磁矩降低一致。对于具有 10 wt% CFO 相的复合材料，在 1 MHz 下获得最大介电常数值 e' ∼ 678。