Self-assembled nanocomposite films containing ferroelectric and ferromagnetic phases have attracted enormous research interest because they are the most promising candidates for practical multiferroic applications. However, obtaining a genuine magnetoelectric (ME) coupling effect is still challenging in this research area. To substantially improve the ME effect, new heterostructure designs with efficient strain control between two phases are urgently needed. Herein, a novel three-dimensional (3D) nanocup architecture of a heterostructure film is developed. To establish the unique architecture, a heavily Co, Fe-doped ferroelectric Bi_3.25La_0.75Ti₃O₁₂ (BLT) target was used during the growth of BLT thin films via pulsed laser deposition. Consequently, 3D nanocup-structured CoFe₂O₄ (CFO) particles formed inside the BLT via spontaneous nucleation and agglomeration. The 3D nanocup BLT-CFO film exhibited magnetically controlled reversible dielectric switching, which is direct evidence of strong ME coupling caused by the efficient interfacial strain coupling and low leakage of the novel nanocup architecture. The obtained results strongly suggest that the 3D nanocup heterostructure film significantly improves the ME coupling effect. In addition, we propose a new paradigm in the architecture design of self-assembled nanocomposite films for diverse multifunctional devices.

包含铁电相和铁磁相的自组装纳米复合薄膜吸引了巨大的研究兴趣，因为它们是实际多铁应用的最有希望的候选者。但是，在该研究领域中，获得真正的磁电（ME）耦合效果仍然是一项挑战。为了显着改善ME效果，迫切需要在两相之间具有有效应变控制的新型异质结构设计。本文中，开发了异质结构膜的新颖的三维（3D）纳米杯结构。为了建立独特的体系结构，需要使用重掺杂Co的铁铁Bi _3.25 La _0.75 Ti ₃ O ₁₂（BLT）靶材是通过脉冲激光沉积在BLT薄膜的生长过程中使用的。因此，3D纳米杯结构的CoFe ₂ O ₄（CFO）颗粒通过自发成核和附聚形成在BLT内部。3D纳米杯BLT-CFO膜表现出磁控可逆介电开关，这是有效的界面应变耦合和新型纳米杯结构的低泄漏引起的强ME耦合的直接证据。所获得的结果强烈暗示3D纳米杯异质结构膜显着改善了ME偶联效果。此外，我们在用于各种多功能设备的自组装纳米复合薄膜的体系结构设计中提出了新的范例。