Creation of Switching Systems of Superparamagnets by External Stimulus

本计画的目的是借由外加刺激的切换，在超顺磁性体中创造新的物理性质与功能。我们采用的一种策略是制备导电的SMM，如[Pc_2Tb] Cl_（0.6），其阻断温度为47K，其磁性在10K以下显示磁滞。这种SMM在低于8K时表现出负磁阻效应。在我们的第二种策略中，我们将平面存储器并入双层Tb（III）SMM（Pc_2Tb）中。此外，我们还首次用扫描隧道谱（STS）观测到了4.8K下的近藤效应。我们可以通过使用STS注入电子来控制近藤峰的出现和消失。这被认为是第一个单分子存储设备。在我们的第三种策略中，我们已经制备了SMM的场效应晶体管（FET）器件。Pc2Dy器件显示双极（n型和p型）行为，而Pc2Tb器件显示p型行为。这种差异是由镧系元素离子的能级解释的。在第四种方案中，我们将Cs原子掺杂到Pc_2Y上。虽然Pc_2Y分子中的近藤峰是由于Pc配体中的未成对自旋引起的，但当掺杂时，由于自由基Pc与Cs原子的6s电子的耦合，没有观察到近藤峰。最后，通过掺杂和操纵Cs原子，我们可以写出字母T和U，这是东北大学的首字母。

Our purposes of this project are to create the new physical properties and functionalities in superparamagnets by switched with the external stimulus. One strategy that we have employed is to prepare conducting SMMs, like [Pc_2Tb]Cl_0.6, which has a blocking temperature of 47K and whose magnetic properties showed hysteresis below 10K. This SMM shows negative magnetoresistance below 8 K. In our second strategy, we have incorporated planar memory into a double-decker Tb(III) SMM (Pc_2Tb). In addition, we have observed a Kondo Effect at 4.8 K by using scanning tunneling spectroscopy (STS) for the first time. We can control the appearance and disappearance of the Kondo peak by injecting an electron using an STS. This is considered to be the first single-molecule memory device. In our third strategy, we have prepared field effect transistor (FET) devices of SMMs. The Pc2Dy device shows ambipolar (n- and p-type) behavior, whereas the Pc2Tb device shows p-type behavior. This difference is explained by the energy levels of the lanthanide ions. In the fourth strategy, we have doped Cs atoms onto Pc_2Y. Although Pc_2Y molecules show Kondo peaks due to the unpaired spin in the Pc ligand, when doped, Kondo peaks are not observed due to coupling of the radical Pc and the 6s electrons of the Cs atom. Finally, by doping with and manipulating the Cs atoms, we could write the letters T and U, which are the initials of Tohoku University.