Kim Jeongjun, Kim Han Gyeol, Dho Joonghoe
Department of Physics, Kyungpook National University, Daegu, 41566, South Korea.
Small. 2025 Mar;21(10):e2411966. doi: 10.1002/smll.202411966. Epub 2025 Jan 26.
The construction of multilevel magnetic states using materials with perpendicular magnetic anisotropy (PMA) offers a novel approach to enhancing the storage density and read/write efficiency of nonvolatile magnetic memory devices. In this study, optically readable multilevel magnetic domain states are achieved by inducing asymmetric interlayer interactions and decoupling the magnetic reversal behavior of individual ferromagnetic (FM) layers in exchange-biased FM multilayers with PMA. Hepta-level magnetic domain states are formed in [Co/Pt] FM multilayers grown on an antiferromagnetic FeO layer within a relatively low magnetic field range of ∼±400 Oe. Raising and lowering operations between states are demonstrated to be achievable, enabling the writing of new information without the need for initialization in multilevel magnetic memory applications. This design concept, leveraging multilevel magnetic domain states and facilitating noncontact optical reading of stored information, demonstrates the potential to enhance the storage density of nonvolatile magnetic memory devices as it eliminates the need for electrical circuits typically required in other resistive memory technologies.
利用具有垂直磁各向异性(PMA)的材料构建多级磁态,为提高非易失性磁存储器件的存储密度和读/写效率提供了一种新方法。在本研究中,通过诱导不对称层间相互作用并解耦具有PMA的交换偏置铁磁(FM)多层膜中各个铁磁层的磁反转行为,实现了光学可读的多级磁畴态。在反铁磁FeO层上生长的[Co/Pt] FM多层膜中,在约±400 Oe的相对低磁场范围内形成了七能级磁畴态。证明了状态之间的上升和下降操作是可行的,这使得在多级磁存储应用中无需初始化即可写入新信息。这种设计概念利用了多级磁畴态并便于对存储信息进行非接触光学读取,由于消除了其他电阻式存储技术通常所需的电路,展示了提高非易失性磁存储器件存储密度的潜力。