Author ORCID Identifier

Defense Date


Document Type


Degree Name

Master of Science


Mechanical and Nuclear Engineering

First Advisor

Dr. Jayasimha Atulasimha


Nanomagnetic random-access-memory (RAM) devices are considered one of the leading alternatives to the existing Complementary Metal Oxide Semiconductor (CMOS) based RAM devices due to inherent non-volatility and long endurance compared to other non-CMOS devices. However, new paradigms such as voltage control and spin orbit torque are being explored to write information with low errors in an energy efficient manner. Magnetic skyrmions have emerged as potentially viable paradigm for nanomagnetic memory devices because of their robustness, scalability and extremely low energy requirement for creation and manipulation. Besides, electric field induced manipulation of nanomagnets as well as magnetic skyrmions has been shown to be a promising strategy towards the implementation of ultra-low power memory devices.

One such electric field-based manipulation of magnetic states involves skyrmion mediated switching of perpendicular magnetic tunnel junctions (p-MTJs) based nanomagnetic memory devices. This is achieved by applying a voltage pulse starting from a ferromagnetic up/down state to reduce PMA, thus creating an intermediate skyrmion and subsequently annihilating the skyrmion by withdrawing the voltage pulse to achieve ferromagnetic down/up (i.e. reversed) state. However, scalability of skyrmions confined in a nanodot and skyrmion-mediated voltage-controlled switching strategy have not been completely investigated, particularly their scaling to 20 nm lateral dimension and beyond. In this study, we investigated the feasibility of scaling of perpendicular MTJs to lateral dimensions ~20nm and beyond, as well as dynamic skyrmion-mediated switching in such MTJs in the presence of room temperature thermal noise and defects/edge roughness.


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