Spin Solar Cell Phenomenon on a Single-Molecule Magnet (SMM) Impacted CoFeB-Based Magnetic Tunnel Junctions
Spin Solar Cell Phenomenon on a Single-Molecule Magnet (SMM) Impacted CoFeB-Based Magnetic Tunnel Junctions
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DOI：
10.1021/acsaelm.3c00369
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发表时间：
2023-05-31
影响因子：
4.7
通讯作者：
Tyagi，Pawan
中科院分区：
文献类型：
--
作者：
Savadkoohi，Marzieh;Gopman，Daniel;Tyagi，Pawan
单分子磁铁（SMM）在这里展示了将传统的磁隧道结（MTJs），一种用于当今计算机的存储设备，转化为太阳能电池。在非偏振光照射下，我们首次在smm转换的MTJ上展示了电子自旋依赖的太阳能电池效应。我们设计了交叉结形状的器件，形成了CoFeB/MgO/CoFeB-based MTJ。两个暴露结边缘交点处的MgO势垒厚度小于SMM范围，这使得SMM分子能够作为通道进行自旋相关输运。SMM通道在这些工程分子结周围产生了一个远程磁有序区域。我们的SMM具有六核[Mn6(μ3-O)2(H2N-sao)6(6-atha)2(EtOH)6] [H2N-saoH =水杨胺肟，6-atha = 6-乙酰硫代己酸盐]配合物和端基硫酯与金属薄膜形成键。smm掺杂的MTJs表现出太阳电池效应，在一个太阳等效辐射剂量的照射下产生≈80 mV开路电压和≈10 mA/cm2饱和电流密度。一项室温开尔文探针AFM （kafm）研究提供了直接证据，证明SMM在一个横向区域上改变MTJ电极的电子特性，其范围比分子结本身所跨越的区域大几千倍。观察到这种自旋光伏效应的决定性因素是在两个不同的铁磁电极之间形成了SMM自旋通道，这反过来又能够催化结区周围每个电极的远程转变。
The single-molecule magnet (SMM) is demonstrated here to transform conventional magnetic tunnel junctions (MTJs), a memory device used in present-day computers, into solar cells. For the first time, we demonstrated an electronic spin-dependent solar cell effect on an SMM-transformed MTJ under illumination from unpolarized white light. We patterned cross-junction-shaped devices to form a CoFeB/MgO/CoFeB-based MTJ. The MgO barrier thickness at the intersection between the two exposed junction edges was less than the SMM extent, which enabled the SMM molecules to serve as channels to conduct spin-dependent transport. The SMM channels yielded a region of long-range magnetic ordering around these engineered molecular junctions. Our SMM possessed a hexanuclear [Mn6(μ3-O)2(H2N-sao)6(6-atha)2(EtOH)6] [H2N-saoH = salicylamidoxime, 6-atha = 6-acetylthiohexanoate] complex and thioesters end groups to form bonds with metal films. SMM-doped MTJs were shown to exhibit a solar cell effect and yielded ≈80 mV open-circuit voltage and ≈10 mA/cm2saturation current density under illumination from one sun equivalent radiation dose. A room-temperature Kelvin Probe AFM (KPAFM) study provided direct evidence that the SMM transformed the electronic properties of the MTJ’s electrodes over a lateral area in excess of several thousand times larger in extent than the area spanned by the molecular junctions themselves. The decisive factor in observing this spin-photovoltaic effect is the formation of SMM spin channels between the two different ferromagnetic electrodes, which in turn is able to catalyze the long-range transformation in each electrode around the junction area.