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New Material for Generating Energy-Efficient Spin Currents
(Professor Byong-Guk Park (left) and Professor Kab-Jin Kim)
Magnetic random access memory (MRAM) is emerging as next-generation memory. It allows information to be kept even without an external power supply and its unique blend of high density and high speed operation is driving global semiconductor manufacturers to develop new versions continuously.
A KAIST team, led by Professor Byong-Guk Park in the Department of Materials Science and Engineering and Professor Kab-Jin Kim in the Department of Physics, recently has developed a new material which enables the efficient generation of a spin current, the core part of operating MRAM. This new material consisting of ferromagnet-transition metal bilayers can randomly control the direction of the generated spin current unlike the existing ones.
They also described a mechanism for spin-current generation at the interface between the bottom ferromagnetic layer and the non-magnetic spacer layer, which gives torques on the top magnetic layer that are consistent with the measured magnetization dependence.
When applying this to spin-orbit torque magnetic memory, it shows the increased efficiency of spin torque and generation of the spin current without an external magnetic field. High-speed operation, the distinct feature of spin-orbit torque-based MRAM that carries its non-volatility, can significantly reduce the standby power better than SRAM.
This new material will expect to speed up the commercialization of MRAM. The research team said that this magnetic memory will further be applied to mobile, wearable, and IoT devices.
This study, conducted in collaboration with Professor Kyung-Jin Lee from Korea University and Dr. Mark Stiles from the National Institute of Standards and Technology in the US, was featured in Nature Materials in March. The research was funded by the Creative Materials Discovery Program of the Ministry of Science and ICT.
(Figure: Ferromagnet-transition metal bilayers which can randomly control the direction of the generated spin current)
2018.05.11 View 8836 -
KAIST Team Wins Bronze Medal at Int'l Programming Contest
A KAIST Team consisting of undergraduate students from the School of Computing and Department of Mathematical Science received a bronze medal and First Problem Solver award at an international undergraduate programming competition, The Association for Computing Machinery-International Collegiate Programming Contest (ACM-ICPC) World Finals.
The 41st ACM-ICPC hosted by ACM and funded by IBM was held in South Dakota in the US on May 25. The competition, first held in 1977, is aimed at undergraduate students from around the world. A total of 50,000 students from 2900 universities and 103 countries participated in the regional competition and 400 students competed in the finals.
The competition required teams of three to solve 12 problems. The KAIST team was coached by Emeritus Professor Sung-Yong Shin and Professor Taisook Han. The student contestants were Jihoon Ko and Hanpil Kang from the School of Computing and Jongwoon Lee from the Department of Mathematical Science. The team finished ranked 9th, receiving a bronze medal and a $3000 prize. Additionally, the team was the first to solve all the problems and received the First Problem Solver award. Detailed score information can be found on. https://icpc.baylor.edu/scoreboard/
(Photo caption: Professor Taisook Han and his students)
2017.06.12 View 8161 -
KAIST Announces the Recipients of Distinguished Alumni Awards
The KAIST Alumni Association (KAA) announced four “Proud KAIST Alumni” awards recipients for the year 2014: Sung-Wook Park, the Chief Executive Officer and President of SK Hynix; Seung Ho Shin, the President of Kangwon National University; Kew-Ho Lee, the President of the Korea Research Institute of Chemical Technology; and Mun-Kee Choi, the former Minister of Science, ICT and Future Planning of the Republic of Korea. The award ceremony took place during the 2015 KAA’s New Year's ceremony on January 17, 2015 at the Palace Hotel in Seoul.
Sung-Wook Park (M.S. ’82 and Ph.D. ’88, Department of Materials Science and Engineering), the Chief Executive Officer and President of SK Hynix, has worked as an expert in the field of memory semi-conductors for the past 30 years. He developed innovative technology and improved production efficiency, enabling the Korean semi-conductor industry to become a global leader.
Seung Ho Shin (M.S. ’79 and Ph.D. ’87, Department of Physics), the President of Kangwon National University (KNU), worked in the field of optical information processing, producing excellent research achievements and teaching the next generation of scientists. As the president of KNU, he has set an exemplary leadership in higher education.
Kew-Ho Lee (M.S. ’75, Department of Chemistry), the President of the Korea Research Institute of Chemical Technology, pioneered the field of separation film production which contributed greatly to Korean technological developments. He led several domestic and international societies to facilitate dynamic exchanges between industry and academia and with the international community.
Mun-Kee Choi (M.S. ’76, Department of Industrial and Systems Engineering), the former Minister of Science, ICT and Future Planning, the Republic of Korea, is a great contributor to the information and communications technology in Korea, working as a leader in the field of broadband integrated service digital network. He is also an educator for gifted students in science and technology, and a manager of the Electronics and Telecommunications Research Institute.
The Alumni Association established the “Proud KAIST Alumni Awards” in 1992 to recognize its alumni’s outstanding contributions to Korea and KAIST.
Pictured from left to right, Sung-Wook Park (the Chief Executive Officer and President of SK Hynix), Seung Ho Shin (the President of Kangwon National University), Kew-Ho Lee (the President of the Korea Research Institute of Chemical Technology), and Mun-Kee Choi (the former Minister of Science, ICT and Future Planning)
2015.01.19 View 12791 -
Extracting Light from Graphite: Core Technology of Graphene Quantum Dots Display Developed
Professor Seokwoo Jeon of the Department of Materials Science and Engineering, Professor Yong-Hoon Cho of the Department of Physics, and Professor Seunghyup Yoo of the Department of Electrical Engineering announced that they were able to develop topnotch graphene quantum dots from graphite.
Using the method of synthesizing graphite intercalation compound from graphite with salt and water, the research team developed graphene quantum dots in an ecofriendly way.
The quantum dots have a diameter of 5 nanometers with their sizes equal and yield high quantum efficiency. Unlike conventional quantum dots, they are not comprised of toxic materials such as lead or cadmium. As the quantum dots can be developed from materials which can be easily found in the nature, researchers look forward to putting these into mass production at low cost.
The research team also discovered a luminescence mechanism of graphene quantum dots and confirmed the possibility of commercial use by developing quantum dot light-emitting diodes with brightness of 1,000 cd/m2, which is greater than that of cellphone displays.
Professor Seokwoo Jeon said, “Although quantum dot LEDs have a lower luminous efficiency than existing ones, their luminescent property can be further improved” and emphasized that “using quantum dot displays will allow us to develop not only paper-thin displays but also flexible ones.”
Sponsored by Graphene Research Center in KAIST Institute for NanoCentury, the research finding was published online in the April 20th issue of Advanced Optical Materials.
Picture 1: Graphene quantum dots and their synthesis
Picture 2: Luminescence mechanism of graphene quantum dots
Picture 3: Structure of graphene quantum dots LED and its emission
2014.09.06 View 15973