Albeit having great potential toward unprecedented type of applications such as magnetoelectric (ME) sensors and memories, practically useful single‐phase multiferroics that show large coupling between ferromagnetism and ferroelectricity at ambient temperatures are still lacking. Here, the discovery of a new type of perovskite ferroelectrics (Pb,M)(Fe1/2Nb1/2)O3 (M = Fe, Co, Ni) is reported with a magnetically‐active metal ion introduced into a cuboctahedrally‐coordinated Pb position, which exhibits enhanced ME coupling owing to the development of simultaneous soft‐ferromagnetism and lone‐pair ferroelectricity persistent above room temperature. These Pb‐site engineered (Pb,M)(Fe1/2Nb1/2)O3 perovskites exhibit a ME coupling coefficient of ≈40–60 ps m−1, a saturated electric polarization of 14–17 µC cm−2 and a saturation magnetization of 0.15–0.3 µB f.u−1. X‐ray absorption spectroscopy combined with first‐principles calculations demonstrates that the induced ferromagnetism originates from the ferromagnetic superexchange interaction coming from ≈90° bonding between the magnetic ions at the Pb site. The present discovery of the enhanced ME coupling in the Pb‐site engineered perovskite ferroelectrics may provide unforeseen opportunities for applying conventional displacive ferroelectricity in the field of spintronics where ferromagnetism is essentially required.

中文翻译：

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Pb-site 改性 PbFe1/2Nb1/2O3 中软铁磁性与位移铁电之间的增强耦合


尽管在磁电 （ME） 传感器和存储器等前所未有的应用类型中具有巨大潜力，但在环境温度下显示铁磁性和铁电性之间有很大耦合的实用单相多铁器件仍然缺乏。在这里，报道了一种新型钙钛矿铁电体 （Pb，M）（Fe1/2Nb1/2）O3 （M = Fe， Co， Ni） 的发现，其中磁性活性金属离子被引入立方八面体配位的 Pb 位置，由于同时发展软铁磁性和持续在室温以上的孤对铁电性，它表现出增强的 ME 耦合。这些铅位工程 （Pb，M）（Fe1/2Nb1/2）O3 钙钛矿的 ME 耦合系数为 ≈40–60 ps m−1，饱和极化为 14–17 μC cm−2 和 0.15–0.3 μB f.u−1 的饱和磁化强度。X 射线吸收光谱与第一性原理计算相结合，表明感应铁磁性源于 Pb 位点磁离子之间 ≈90° 键合产生的铁磁超交换相互作用。目前在 Pb-site 工程钙钛矿铁电体中发现的增强 ME 耦合可能为在本质上需要铁磁性的自旋电子学领域应用传统的位移铁电性提供不可预见的机会。