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International Affairs Students Current Students Alumni Faculty/Staff Careers--> TOHOKU UNIVERSITYCREATING GLOBAL EXCELLENCE Search 日本語 Contact Tohoku University --> About Facts & Figures Facilities Organization Chart History President's Message Top Global University Project Designated National University Global Network Promotional Videos Academics Undergraduate Graduate Courses in English Exchange Programs Summer Programs Double Degree Programs Academic Calendar Syllabus Admissions Undergraduate Admissions Graduate Admissions Fees and Expenses Financial Aid Research Feature Highlights Research Releases University Research News Research Institutes Visitor Research Center Research Profiles Academic Research Staff Campus Life International Support Office IT Services Facilities Dining & Shops Campus Bus Clubs & Circles News University News Research--> Arts & Culture Health & Sports Campus & Community Press Release--> International Visit Alumni Careers Events Exhibits Music Special Event Lecture Alumni--> Map & Directions Campus Maps & Bus--> Facilities Map--> TOHOKUUNIVERSITY About Academics Admissions Research Campus Life News Events International Affairs Students Current Students Alumni Faculty/Staff Promotional Videos Subscribe to our Newsletter Map & Directions Contact Jobs & Vacancies Emergency Information Site Map 日本語 Close Home Research News Controlling spin for memory storage Research News Controlling spin for memory storage 2017-11-24 Using computer simulations, researchers are learning how lasers might be used to switch how electrons spin within magnetic materials, making room for faster magnetic memory devices. Tohoku University researchers have developed a computational simulation that shows that using ultrafast laser pulses to excite electrons in a magnetic material switches them into a transient non-magnetic state. This could reduce the time involved in manipulating a material's magnetism, improving magnetic storage and information processing technologies. Storing 'bits', or binary digits, of information in magnetic memory devices requires the ability to reverse the magnetism within a material between ferromagnetic and antiferromagnetic. In the ferromagnetic state, the electron spins within the material align parallel to each other and spin in the same direction, making them and the material magnetic. In the antiferromagnetic state, the electron spins align parallel to each other but neighbouring electrons spin in opposite directions, cancelling out each other's effects and making them and the material in which they exist virtually non-magnetic. By applying light, the parallel spin arrangement is changed to antiparallel. Fast memory storage requires rapid spin reversal. Researchers have been studying ways to control this using ultrafast lasers to get even faster memory storage. The shorter the laser's pulse, the faster the reversal will be. Tohoku University physicists Atsushi Ono and Sumio Ishihara developed a computational approach to model how electrons and their spins interact with each other and react to laser light. They found that exposing electrons in ferromagnetic materials to a continuous laser light makes them excited, causing electron interactions that lead to an antiferromagnetic state. Applying ultrafast light pulses also leads to switching from ferromagnetism to transient antiferromagnetism, followed by recovery of ferromagnetism. When the researchers applied an ultrafast laser pulse followed by a continuous laser light, the electrons were manipulated into an antiferromagnetic state that was then maintained by the continuous light. Removing the continuous light caused the gradual disappearance of the antiferromagnetic state. Understanding these interactions, as well as the fundamental limits of spin reversal, is necessary for future development of magnetic memory devices. The next step will require physical experiments to test the model's predictions. "Experimental confirmations are indispensable for establishing the present proposal," write the researchers in their study published in the journal Physical Review Letters. Ono and Ishihara suggest perovskite manganites and layered manganites as possible materials for testing their model. They also suggest a variety of techniques, such as magnetic x-ray diffraction and photoemission spectroscopy, for observing the transient antiferromagnetic state. Publication Details: Title: Double-Exchange Interaction in Optically Induced Nonequilibrium State: A Conversion from Ferromagnetic to Antiferromagnetic StructureAuthors: Atsushi Ono and Sumio Ishihara Journal: Physical Review Letters DOI: 10.1103/PhysRevLett.119.207202 Press release in Japanese Contact: Sumio Ishihara Department of Physics Graduate School of Science E-mail: [email protected] Archives 2014&＃24180; 2015&＃24180; 2016&＃24180; 2017&＃24180; 2018&＃24180; 2019&＃24180; 2020&＃24180; 2021&＃24180; 2022&＃24180; 2023&＃24180; Page Top About Tohoku University Academics Admissions Research Campus Life News Events International Affairs Students Alumni Promotional Videos Subscribe to our Newsletter Map & Directions Contact Tohoku University Jobs & Vacancies Emergency Information Site Map Media Enquiries Parent & Family Support Public Facilities Contact Tohoku University