Magnetic tunnel junctions (MTJ) is a key technology in modern spintronics because it is the basis of read-heads of modern hard disk drives, non-volatile magnetic random access memories, and sensor application. In this paper, we demonstrate that the tunneling magneto-resistance (TMR) can influence terahertz (THz) wave propagation through a MTJ. In particular, various magnetic configurations between parallel (P) state and antiparallel (AP) state of the magnetizations of the ferromagnetic layers in the MTJ have the effect on changing the conductivity, making a functional modulation of the propagating THz electromagnetic fields. Operating at the THz frequency range, a maximal modulation depth of 60{%} is reached for the P state of the MTJ with the thickness of 77.45 nm, using a magnetic field as low as 30 mT. The THz conductivity spectrum of the MTJ is governed by the spin-dependent electron tunneling. It is anticipated that MTJ device and its tunability scheme will have many potential applications in THz magnetic modulators, filtering and sensing.

中文翻译：

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基于磁隧道结的自旋极化电子隧穿对太赫兹波的磁调制

磁性隧道结（MTJ）是现代自旋电子学中的一项关键技术，因为它是现代硬盘驱动器，非易失性磁性随机存取存储器和传感器应用的读取头的基础。在本文中，我们证明了隧道磁阻（TMR）可以影响太赫兹（THz）波通过MTJ的传播。尤其是，MTJ中铁磁层的磁化强度在平行（P）状态和反平行（AP）状态之间的各种磁性结构对改变电导率有影响，从而对传播的太赫兹电磁场进行功能调制。在太赫兹频率范围内工作，使用低至30 mT的磁场，对于厚度为77.45 nm的MTJ的P态，最大调制深度达到60 {％}。MTJ的THz电导率谱受自旋相关电子隧穿的支配。预计MTJ器件及其可调性方案将在THz磁调制器，滤波和传感中具有许多潜在应用。