Researchers have used terahertz light pulses to induce ferromagnetism in a crystal at temperatures far above its normal transition temperature, paving the way for optically controlled memory and computing devices with higher speed and efficiency.
Scientists in Germany and the USA have shown for the first time that terahertz (THz) light pulses can stabilize ferromagnetism in a crystal at temperatures more than three times its usual transition temperature. As the team reports in the journal Nature, using pulses just hundreds of femtoseconds long (a millionth of a billionth of a second), a ferromagnetic state was induced at high temperature in the rare-earth titanate YTiO3 which persisted for many nanoseconds after the light exposure. Below the equilibrium transition temperature, the laser pulses still strengthened the existing magnetic state, increasing the magnetization up to its theoretical limit.
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