Voltage Control of Perpendicular Magnetic Anisotropy in Multiferroic Composite Thin Films under Strong Electric Fields
Voltage Control of Perpendicular Magnetic Anisotropy in Multiferroic Composite Thin Films under Strong Electric Fields
复制标题
强电场下多铁复合薄膜垂直磁各向异性的电压控制
DOI：
10.1021/acsami.1c16582
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发表时间：
2021
影响因子：
9.5
通讯作者：
Ming Liu
中科院分区：
文献类型：
--
作者：
Bin Peng;Haowen Tang;Yuxing Chen;Yao Zhang;Ruibin Qiu;Qi Lu;Ziyao Zhou;Ming Liu
具有垂直磁各向异性（PMA）的“铁电/铁磁”多铁性复合材料可用于开发功率高效的磁存储器。PMA的电压控制已经在基于铁电单晶的块体多铁性复合材料中得到证实，但是它们不兼容于集成。多铁性复合薄膜可用于开发集成器件，然而，由于它们的低磁电（ME）耦合系数，在室温下尚未实现PMA的电压控制。在这里，我们展示了这样的功能，并建议通过充分利用铁电薄膜的大介电强度，在强电场下增强它们的ME耦合效应。首先，研究了Pb（Zr0.384Ti0.576Nb0.04）O3（PNZT）薄膜的厚度依赖击穿特性，双层（约200 nm）样品具有最高的击穿强度（3.68 MV/cm）和较小的表面粗糙度（<1 nm）。其次，我们制备了具有强PMA的“PNZT/（Co/Pt）5”薄膜，其击穿强度几乎与顶部电极材料无关。最后，研究了PNZT/（Co/Pt）5薄膜的电压感应有效磁场（Heff）。这是可比的，在散装复合材料中实现，并会诱导磁化切换下的强电场。具有高击穿强度的多铁性复合薄膜将为实现集成多铁性器件提供一个有用的平台。
“Ferroelectric/ferromagnetic” multiferroic composites with perpendicular magnetic anisotropy (PMA) are useful for developing power-efficient magnetic memories. Voltage control of PMA has been demonstrated in bulk multiferroic composites based on ferroelectric single crystals, but they are not compatible for integration. Multiferroic composite thin films are useful for developing integrated devices; however, voltage control of PMA in them has not been achieved yet at room temperature due to their low magnetoelectric (ME) coupling coefficient. Here, we demonstrate such functionality and propose to enhance their ME coupling effect under a strong electric field by taking full advantage of the large dielectric strength of ferroelectric thin films. First, the thickness-dependent breakdown of Pb(Zr0.384Ti0.576Nb0.04)O3(PNZT) thin films was studied, and the two-layer (∼200 nm) samples exhibited the highest breakdown strength (3.68 MV/cm) and small surface roughness (<1 nm). Second, we fabricated “PNZT/(Co/Pt)5” thin films with strong PMA whose breakdown strength is nearly independent of the top electrode materials. Finally, voltage-induced effective magnetic field (Heff) in “PNZT/(Co/Pt)5” was studied. It is comparable to that achieved in bulk composites and will induce magnetization switching under strong electric fields. Multiferroic composite thin films with large breakdown strength will provide a useful platform for enabling integrated multiferroic devices.