Chaurasiya Avinash, Anand Manish, Rawat Rajdeep Singh
Natural Sciences and Science Education, NIE, Nanyang Technological University, 637616, Singapore.
Department of Physics, Bihar National College, Patna University, Patna-800004, India.
J Phys Condens Matter. 2022 May 3;34(27). doi: 10.1088/1361-648X/ac66b5.
Using extensive numerical simulations, we probe the magnetization switching in a two-dimensional artificial spin ice (ASI) system consisting of peanut-shaped nanomagnets. We also investigated the effect of external magnetic field on the degeneracy of the magnetic states in such a system. The switching field is found to be one order smaller in the proposed ASI system with peanut-shaped nanomagnets as compared to the conventionally used highly-anisotropic nanoisland such as elliptically shaped nanomagnets. The metastable two-in/two-out (Type II) magnetic state is robust at the remanence. We are also able to access the other possible microstate corresponding to Type II magnetic configurations by carefully varying the external magnetic field. It implies that one can control the degeneracy of the magnetic state by an application of suitable magnetic field. Interestingly, the magnetic charge neutrality at the vertex breaks due to the defects induced by removing nanomagnets. In such a case, the system also appears to have one-out/three-in or three-out/one-in (Type III) spin state, reminiscent of magnetic monopole at the vertex. We believe that our study is highly desirable in the context of developing the next-generation spintronics-based devices for future technologies.
通过广泛的数值模拟，我们探究了由花生形状的纳米磁体组成的二维人工自旋冰（ASI）系统中的磁化翻转。我们还研究了外部磁场对该系统中磁态简并性的影响。结果发现，与传统使用的高度各向异性的纳米岛（如椭圆形纳米磁体）相比，所提出的具有花生形状纳米磁体的ASI系统中的翻转场小一个数量级。亚稳态的双入/双出（II型）磁态在剩磁时很稳定。通过仔细改变外部磁场，我们还能够获得与II型磁构型相对应的其他可能的微观状态。这意味着可以通过施加合适的磁场来控制磁态的简并性。有趣的是，由于去除纳米磁体所诱导的缺陷，顶点处的磁荷中性被打破。在这种情况下，系统还似乎具有单出/三入或三出/单入（III型）自旋态，让人联想到顶点处的磁单极子。我们相信，在为未来技术开发下一代基于自旋电子学的器件的背景下，我们的研究非常有必要。
