2019 Materials Research Society fall meeting

Research professor B. C. Park in our lab attended the '2019 Materials Research Society fall meeting' held in Boston on Dec. 1 ~ 6, 2019.

연구교수 박범철이 12월 1 ~ 6일 보스턴에서 개최된 '2019 Materials Research Society fall meeting'에 참석하였다.

발표내용

  • 박범철 (Poster) : Crystallization pathway controlled microstructural evolution of magnetite mesocrystals

 

How to store cipher data in magnetic skyrmions

Scientists of Far Eastern Federal University (FEFU) with international collaborators propose direct magnetic writing of skyrmions, i.e. magnetic quasiparticles, and skyrmion lattices, within which it is possible to encode, transmit, process information, and produce topological patterns with a resolution of less than 100 nanometers.

This brings closer miniaturized post-silicon electronics, new topological cryptography techniques, and green data centers, reducing the load on the Earth's ecosystem significantly.

A related paper appears in ACS Nano ("Magnetic Direct-Write Skyrmion Nanolithography").

Skyrmion lattice formation. (Image: FEFU)

International scientific teams are intensively looking for alternative materials and approaches to replace silicon electronics devices based on CMOS technology (complementary metal-oxide-semiconductor). The major drawback of this technology is the size of contemporary transistors based on it. Physical impossibility to further miniaturizing them implies the future development of the electronics industry is under question.

One of the promising alternatives to CMOS transistors is thin-film magnetic materials with layers from one to several nanometers thick, in which skyrmions, nontrivial magnetic structures, are formed under certain conditions.

In the study, researchers claim they have designed close-packed stable arrays of skyrmions via affecting a thin-film magnetic structure by the local magnetic field of a magnetic force microscope probe.

Thus, the team pioneered topological nanolithography, getting nanoscale topological patterns where each individual skyrmion acts as a pixel, just like in digital photography. Such skyrmion pixels are not visible in the optical range and to decode them, as well as to create them, one needs a magnetic force microscope.

"Skyrmions driven by current pulses can be used as basic elements mimic the action potential of biological neurons to create neuromorphic chips. Arrays of chips with each tiny neuron element communicating with another one by means of moving and interacting skyrmions, will have energy efficiency and high computing power", says Alexander Samardak, one of the authors of the research idea, FEFU Vice-President for Research. "Another interesting field is visual or topological cryptography. In that case, a message is encrypted as a topological pattern which is a set of ordered skyrmions. Deciphering such a message will require, first, knowledge of the coordinates of the nanoscale image and, second, the availability of a special gear as a magnetic force microscope with high sensitivity to stray fields of skyrmions. Attempting to hack the message with incorrectly selected parameters for reading the topological image will lead to its destruction. Currently, about 25 MB of information can be recorded on a square millimeter of a magnetic thin film. By reducing the size of skyrmions to 10 nm, a capacity of 2.5 Gb / mm2 can be achieved."

The limitation of the approach is that the speed of recording of information with local point magnetic fields. It is still very slow, which curbs the approach from mass implementation.

Alexander Samardak said that the team learned how to regulate the size and density of the skyrmions packing, controlling the scanning step (a distance between two adjacent scanning lines) with a probe of the magnetic force microscope. It expands the possible future applications.

For example, if the skyrmions have a size of less than 100 nanometers, they can be used as a base for reservoir computing, reconfigurable logic, and magnonic crystals which are the basis of magnonic processors and microwave communication devices in the sub-THz and THz range. Such devices will be much more energy-efficient compared to existing electronics. That paves the way for future green and high-performance data centers.

"Skyrmion can be a carrier of information bits. That is possible due to the skyrmion polarization, i.e. positions "up" or "down" which relates to well-known "0" or "1". Hence, skyrmions can be basic elements for magnetic or racetrack memory. Such devices, in contrast to hard magnetic disks, will have no mechanical parts, bits of information will move by themselves. Moreover, ordered two-dimensional arrays of skyrmions can play the role of artificial magnonic crystals, through which not electric current but spin waves propagate transmitting information from a source to a receiver without heating the working elements," Alexey Ognev says, the first author of the article, Head of the FEFU Laboratory for thin-film technologies.

Using the developed technology, scientists plan to scale down the size of skyrmions and develop practical devices based on them.

 

Far eastern Federal University, "How to store cipher data in magnetic skyrmions", 2020년 11월 30일, www.nanowerk.com/nanotechnology-news2/newsid=56726.php

Magnetic Direct-Write Skyrmion Nanolithography ACS Nano 14, 14960–14970 (2020)
[doi: 10.1021/acsnano.0c04748]

The 31st Joint Interlaboratory Workshop on Nano-Magnetics (JIWON)

Our laboratory members attended 'The 31st Joint Interlaboratory Workshop on Nano-Magnetics' held in Sendai, Japan on  January 27 ~ 30, 2020.

 

일본 Tohoku대 전자공학과 Sahashi교수님 연구실, Far Eastern Federal University (FEFU) 연구실과 31번째 JIWON 워크샵을 가졌다. 

2019 Homecoming Day

Current researchers held Homecoming day in Yangjae, Korea on December 14, 2019

12월 14일 양재 갈비사랑에서 홈커밍데이를 열었다.

2019 International Symposium on Magnetism and Magnetic Materials (2019 한국자기학회 동계학술대회 참석)

Graduate students in our lab, G. W. Kim and Thomas M. S. Koo attended the '2019 International Symposium on Magnetism and Magnetic Materials' held in Jeju Korea on Nov. 20 ~ 22, 2019.

Thomas M. S. Koo received the best poster award.

11월 20 ~ 22 일 제주에서 개최된 2019 한국자기학회 동계학술대회에 참석하였다. 이번 동계학술대회에는 대학원생 김규원, 구명석이 참석하였다.

대학원생 구명석은 해당 학술대회에서 우수 포스터 발표상을 수상하였다. 

발표 내용 

  • 김규원 (Oral): Influence of vanadium incorporation on SOT efficiency in W/W-X/CoFeB/MgO structures
  • 구명석 (Poster): Fluorescent detection of Bacterial Spores biomarker using Tb3+ coordinated Fe3O4 Nanoparticles

64th Annual Conference on Magnetism and Magnetic Materials (MMM)

Research professor B. C. Park and graduate student G. W. Kim in our lab attended the '64th Annual Conference on Magnetism and Magnetic Materials' held in Las Vegas USA on Nov. 4 ~ 8, 2019.

연구교수 박범철, 대학원생 김규원이 11월 4~ 8일 미국 라스베이거스에서 개최된 62nd Annual MMM Conference에 참석하였다. 

발표내용

  • 박범철 (Poster) : Control of microstructure of magnetite nanoparticle and their effect on r2 relaxivity for T2 weighted magnetic resonance imaging

  • 김규원 (Oral) : Enhancing spin-orbit torque efficiency using co-sputtering of vanadium in W/CoFeB/MgO structure

2019 Fall Conference of the Korean Institue of Metals and Materials (대한금속재료학회 추계학술대회 참석)

Graduate students in our lab. S. W. Byun, M. S. Kim and Prof. Kim attended 'Fall conference of the Korean Institute of Metals and Materials' held in Daegu, Korea on October 23 ~ 25, 2019.

M. S. Kim has received a best oral presentation award.

대학원생 변상원, 김명수, 그리고 김영근 교수가 10월 23 ~ 25 일 대구에서 개최된 2019 대한금속재료학회 추계학술대회에 참석하였다.
대학원생 김명수는 해당 학술대회에서 학생구두발표 우수상을 수상하였다.


발표 내용 

  • 변상원 (Oral): 항암면역치료를 위한 마이크로 섬유에 방사상으로 성장한 ZnO  나노선과 종양항원 복합체
  • 김명수 (Oral): Engineering of bimetallic layer growth from gold seed assembled on magnetite template for surface-enhanced Raman scattering activity