The research group of Professor Sumio Ishihara of Tohoku University and others found that when a metal magnet is exposed to strong light, the spins of all the electrons change from an array in which they are aligned in the same direction to an array in which they are oriented in opposite directions, and instantly lose their properties as a magnet. We succeeded in showing that by theoretical calculation simulation.
In a magnet, all small magnets called electron spins are arranged in the same direction, and the function of the magnet appears as a whole.It is important to operate spins efficiently and quickly in order to handle a large amount of information at high speed, and it has been required to elucidate the principle.
Recent laser technology has opened up the possibility of operating it in a very short time.So far, it has been known that when light is applied to an insulator in which spins are staggered, all the metals are aligned in the same direction.
The research group is considering the reverse operation.Theoretical calculation that when a metal whose electron spins are all aligned in the same direction is exposed to strong light, the directions are reversed and the magnet properties are lost instantly (10/1 trillion seconds to 1 trillionth of a second). We succeeded in demonstrating by simulation.
All spins are aligned in the same direction in the magnet because parallel forces work during the spins.In the calculation, by shining a laser, it means that the force that makes the spins parallel to each other is converted into the force that makes them antiparallel.The force that parallelizes spins, which have the properties of magnets, was discovered in the 1950s.For the first time, it was found that this force shows the opposite nature when exposed to strong light.
Studies have shown the mechanism from antiparallel to parallel.It is expected that the combined use of both will enable high-speed operation of the spin array in both directions.Since the spin arrangement and the flow of electricity are closely related, it is expected to provide a guideline for device design using ultrafast switches.
