In this study, we report a detail investigation of structural, morphological, ferroelectric, and ferromagnetic properties of low sintering-temperature lead-free particulate composites of (1−x)(0.98(Bi_0.5(Na_0.78K_0.22)0.5−TiO₃−0.02CuO)−xNiFe₂O₄(x = 0–0.15) by using some techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), ferroelectric hysteresis (P-E), piezoelectric constant (d₃₃), and magnetization (M−H) measurements. The formation of two parent materials in single crystal phases without any impurities was demonstrated by XRD. It was interesting that the spontaneous ferroelectric polarization P_s increased with NFO content, reached maximum value at a concentration of 6 mol% of NFO in composite and then declined gradually with further increase of NFO content. Meanwhile, the maximum strain S_max, normalized strain S_max/E_max (d₃₃^*), and piezoelectric constant d₃₃ exhibited a gradual reduction as NFO content increased. In M-H hysteresis loop measurements, an improvement in saturation magnetization M_s as well as M_r was observed, albeit not proportional, indicating an increase in ferromagetism of composite.

在这项研究中，我们报告了 (1− x )(0.98(Bi _0.5 (Na _0.78 K _0.22 )0.5−TiO ₃的低烧结温度无铅颗粒复合材料的结构、形态、铁电和铁磁性能的详细研究−0.02CuO)−xNiFe ₂ O ₄ ( x  = 0–0.15) 通过使用一些技术，例如X射线衍射 (XRD)、扫描电子显微镜 (SEM)、能量色散光谱 (EDS)、铁电滞后 (PE) , 压电常数 (d ₃₃) 和磁化 (MH) 测量。XRD 证明在单晶相中形成了两种母体材料，没有任何杂质。有趣的是，自发铁电极化 P _s随着 NFO 含量_的增加而增加，在复合材料中 NFO 浓度为 6 mol% 时达到最大值，然后随着 NFO 含量的进一步增加而逐渐下降。同时，随着NFO含量的增加，最大应变S _max、归一化应变S _max /E _max (d ₃₃ ^* )和压电常数d ₃₃表现出逐渐降低。在 MH 磁滞回线测量中，饱和磁化强度 M _s和 M_r被观察到，尽管不成比例，表明复合材料的铁磁性增加。