Special Seminar: Dr. Rana Saha

SPECIAL SEMINAR 

by 

Dr. Rana Saha 

Max Planck Institute of Microstructure Physics, Saxony-Anhalt, Germany.

Title 

Chiral magnetic whirls in future memory devices  

on 

Monday 12^th April 2021 at 9:30 AM  (Through MICROSOFT TEAMS) 

Teams link:  

https://teams.microsoft.com/l/meetup-join/19%3a95b3dfced9714083b3ea8ab65a1c6082%40thread.tacv2/1617675658954?context=%7b%22Tid%22%3a%226f15cd97-f6a7-41e3-b2c5-ad4193976476%22%2c%22Oid%22%3a%22e84c3a28-8bb6-4051-ae4c-080cbb2f1a85%22%7d

Abstract :  

Majority of the world’s digital information today is stored in conventional data storage technologies such as magnetic Hard Disk Drives (HDD) that utilizes extraordinarily sensitive spintronic (spin of electrons as an information carrier in electronics) reading devices, which enabled detection of ever-smaller magnetic bits. However, conventional data storage will reach to its limit in near future due to fundamental limitation of further scaling in two dimensions (2D). At the same time increasing energy consumption of these devices, generate lots of heat leading to wastage of electricity. Therefore, new data storage devices with greater performance and higher energy efficiency is highly demanding. Magnetic Racetrack Memory is a promising proposal for future mass data storage¹, where data bits can be moved in a three-dimensional magnetic nanowire by nanosecond current pulses without any mechanical moving parts unlike in HDD. Racetrack can provide high endurance of HDD, large density of 3D-NAND flash along with attractive latency rates of static random-access memory (SRAM) and dynamic random-access memory (DRAM)².To enable such racetrack memory devices, nanoscopic chiral magnetic textures such as skyrmions³ are potential candidates as magnetic bits. My research focuses on a new type of skyrmion, called “anti-skyrmion”^4-8, discovered by our group. In this talk, I will discuss the interesting static and dynamic properties of anti-skyrmions studied by real-space in-situ magnetic imaging such as, Lorentz Transmission Electron Microscopy and Magnetic Force Microscopy. From these studies we have developed significant fundamental understanding on these fascinating chiral magnetic nano-objects, which are potential for spintronic applications.At the end of this talk, I will also briefly discuss the magnetoelectric effect in transition metal oxidesgiving rise to electric field control of magnetic states or vice-versa^9-10.

References: 

1. Parkin, S. S. P. et al.,  Memory on the racetrack. Nat. Nanotechnol. 10, 195 (2015).
2. Bläsing, R., et al., Magnetic racetrack memory: From physics to the cusp of applications within a decade. Proc. IEEE, (2020).
3. Nagaosa, N. et al., Topological properties and dynamics of magnetic skyrmions. Nat. Nanotechnol. 8, 899 (2013).
4. Nayak, A. K., et al., Magnetic antiskyrmions above room temperature in tetragonal Heusler materials. Nature 548, 561 (2017).
5. Jena, J., et al., Observation of magnetic antiskyrmions in the low magnetization ferrimagnet Mn₂Rh_{0. 95}Ir_{0. 05}Sn. Nano Lett. 20, 59 (2019).
6. Jena, J., et al., Elliptical Bloch skyrmion chiral twins in an antiskyrmion system. Nat. Commun. 11, 1115 (2020).
7. Ma, T., et al., Tunable magnetic antiskyrmion size and helical period from nanometers to micrometers in a D_2d Heusler compound. Adv. Mater. 32, 2002043 (2020).
8. Saha, R., et al., Intrinsic stability of magnetic anti-skyrmions in the tetragonal inverse Heusler compound Mn1.4Pt0.9Pd0.1Sn. Nat. Commun. 10, 5305 (2019).
9. Saha, R. et al., Magnetoelectric effect in simple collinear antiferromagnetic spinels. Phys. Rev. B 94, 014428 (2016).
10. Saha, R. et al., Neutron scattering study of the crystallographic and spin structure in antiferromagnetic EuZrO₃. Phys. Rev. B 93, 014409 (2016).