Magnetization switching in ferromagnets by adsorbed chiral molecules without current or external magnetic field.
Magnetization switching in ferromagnets by adsorbed chiral molecules without current or external magnetic field.
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DOI：
10.1038/ncomms14567
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发表时间：
2017-02-23
影响因子：
16.6
通讯作者：
Paltiel Y
中科院分区：
文献类型：
--
作者：
Ben Dor O;Yochelis S;Radko A;Vankayala K;Capua E;Capua A;Yang SH;Baczewski LT;Parkin SS;Naaman R;Paltiel Y
铁磁体通常被外部磁场或自旋极化电流磁化。自旋电流对磁化的操纵是通过自旋转移力矩效应发生的，例如，该效应应用于现代磁阻随机存取存储器。然而，自旋转移矩所需的电流密度约为1×106 A·cm-2，或约1×1025个电子s-1 cm-2。这种相对较高的电流密度显着影响器件的结构和性能。在这里，我们演示了仅由手性分子吸附引起的铁磁薄层的磁化转变。在这种情况下，每平方厘米大约 1013 个电子足以引起磁化反转。磁化方向取决于吸附的手性分子的旋向性。局部磁化翻转是通过在具有垂直磁各向异性的镀金铁磁层上吸附手性自组装分子单层来实现的。这些结果呈现了在环境条件下运行时的简单低功率磁化机制。存储设备中的自旋操作通常需要大电流，从而限制了性能。在这里，作者通过沉积手性分子演示了铁磁薄膜中的磁化转变，利用邻近效应而不需要磁场或电场。
Ferromagnets are commonly magnetized by either external magnetic fields or spin polarized currents. The manipulation of magnetization by spin-current occurs through the spin-transfer-torque effect, which is applied, for example, in modern magnetoresistive random access memory. However, the current density required for the spin-transfer torque is of the order of 1 × 106 A·cm−2, or about 1 × 1025 electrons s−1 cm−2. This relatively high current density significantly affects the devices' structure and performance. Here we demonstrate magnetization switching of ferromagnetic thin layers that is induced solely by adsorption of chiral molecules. In this case, about 1013 electrons per cm2 are sufficient to induce magnetization reversal. The direction of the magnetization depends on the handedness of the adsorbed chiral molecules. Local magnetization switching is achieved by adsorbing a chiral self-assembled molecular monolayer on a gold-coated ferromagnetic layer with perpendicular magnetic anisotropy. These results present a simple low-power magnetization mechanism when operating at ambient conditions. Spin manipulation in memory devices typically requires large electrical currents, limiting performance. Here the authors demonstrate magnetization switching in ferromagnetic films by depositing chiral molecules, making use of a proximity effect without needing magnetic or electric fields.