Understanding stochasticity of chiral DWs and encoding them for spintronic applications


  • Date: May 15, 2019
  • Time: 11:00 AM (Local Time Germany)
  • Speaker: Khalid Omari
  • University of Nottingham
  • Location: Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle (Saale)
  • Room: Lecture Hall, B.1.11
 Understanding stochasticity of chiral DWs and encoding them for spintronic applications

In Ferromagnetic nanowires, vortex domain walls (VDWs) are mobile chiral magnetic structures that contain spin information representing their internal sense of orientation (chirality). DW chirality affects the dynamic motion trajectory of the DW in nanowires influencing its velocity, pinning states at defects and magnetic switching stochasticity. Additionally, it can be utilized to store and encode information on the same medium.

In this talk I will present a qualitative simulation protocol that can provide a qualitative understanding of how nanowire thickness, shape, as well as defect type affect VDWs stochastcitiy in Permalloy nanowires [1]. Such understanding will lead to understand how undesired dynamic switching stochasticity (induced mainly by Walker-breakdown) can be suppressed to achieve deterministic switching. Moreover, I will present a chirality-based architecture where basic logic gates (NOT, NAND, AND, OR, NOR) can be implemented in a 2-in-1-out network of nanowires where memory and processing can be done on the same architecture [2, 3].

Additionally I will give a brief insight on how graphene-based MTJs can be fabricated and utilized with of the gateable graphene spin channel. Finally I will explain briefly how Antiferromagnetic materials with broken inversion symmetry crystallography can be a promising candidate for an ultra-fast memory application.

[1]: 4. K. A. Omari, T.J. Hayward, A Micromagnetic Protocol for Qualitatively Predicting Stochastic Domain Wall Pinning, Sci. Rep, 7,17862 (2017)

[2]: 1. K. A. Omari and T. J. Hayward, Chirality-Based Vortex Domain-Wall Logic Gates, Phys. Rev. App 2, 044001 (2014)

[3]: 5. K. A. Omari et al, Towards Chirality-Encoded Domain Wall Logic, Adv. Funct. Mater. 29, 1807282 (2019)

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