電圧による交換相互作用と磁化の制御

金属铁磁体的电场控制是制造超低能耗自旋电子学器件的关键技术，因此备受关注。特别是室温下铁磁金属体系的电压诱导磁各向异性变化，针对超低功耗MRAM的应用得到了广泛的研究。电压感应磁学性质已被广泛研究，但三维铁磁体中交换相互作用的电压控制仍在讨论中。此外，Aex中的这种电压控制可以为我们提供磁性材料的新功能，如铁磁性的电压开关、skyrμ子的产生和湮灭、磁振子速度的控制等。因此，JSPS研究员研究了具有垂直磁性自由层的磁性隧道结在电场诱导下的磁性变化。Skyrmions是受拓扑保护的自旋织构，通常起源于不对称交换耦合，即Dzyaloshinskii-Moriya相互作用。最近，由于基于skyrmion的信息设备和信息存储单元的可能性，它受到了吸引。粒子在二维薄膜上的运动可以用牛顿方程的一个修正版本来描述。JSPS研究员研究了在梯度外磁场、梯度磁参数、外加电流和热能等不同力作用下的skyrmions动力学。

Electric field control of magnetic properties in metallic ferromagnets is attracting much attention because of its potential to be a key technology to produce ultralow energy consumption spintronics devices. Especially voltage induced magnetic anisotropy changes in ferromagnetic metal system at room temperature, have been widely studied targeting an ultra-low power MRAM applications. It is widely studied voltage induced magnetic properties, but the voltage control of the exchange interaction in 3d ferromagnets is under discussion. Beside of this, such voltage control in Aex may provide us new functionality of magnetic materials such as voltage switching of ferromagnetism, creation and annihilation of skyrmions, control of magnon velocity, etc. So, JSPS fellow had investigated electric field induced magnetic properties changes on the magnetic tunnel junction with perpendicular magnetic free layer.Skyrmions are topologically protected spin textures which often originated from asymmetric exchange coupling as known Dzyaloshinskii-Moriya interaction. Recently, it has been attracted due to the possibility of the skyrmion based information devices and information storage units. The motion of the skyrmion on two-dimensional film can be described by a modified version of Newton’s equation. JSPS fellow had explored on the skyrmions dynamics under various force such as gradient external magnetic field, gradient magnetic parameters, applying current and thermal energy.