Researchers from the Federal Polytechnic School of Lausanne (EPFL) recently made an amazing discovery about the vanadium dioxide (VO2). This inorganic compound is widely used as catalyst during the manufacture of electronic components. However, scientists have noticed that this compound is also able to “remember” of all the external stimuli it has received.
It’s about first material identified as possessing this property. This discovery, although fortuitous, is unprecedented, because nothing known doesn’t seem to behave that way. In particular, it opens the way to research on materials able to memorize or learn like the brain.
Mohammad Samizadeh NikooPhD student at the Power and Wideband Gap Electronics Research Laboratory (POWERlab) at EPFL, led this team.
Vanadium dioxide exhibits volatile memory
Initially, Samizadeh Nikoo and his team conducted phase transition studies vanadium dioxide. They wanted to determine the necessary time to VO2 for to pass from one state to another. VO2 presents an insulating phase when relaxed at room temperature, and undergoes an abrupt transition insulation to metal at 68°C.
Typically, this compound has volatile memory. The material then returns to the insulating state right after the excitement stops. However, after carrying out hundreds of measurements, they observed a memory effect in the structure of the material.
A memory of up to three hours
During his experiences, Samizadeh Nikoo has applied an electric current to a VO2 sample. The latter passes through the sample and warms it up. vanadium dioxide then returns to its initial state once the current has finished flowing through it.
However, the researcher found that the necessary time at the change of state was directly linked to the history of the material. VO2 seemed remember “ of the first phase transition and anticipate the next. This memory effect has nothing to do with electronic states, but rather with physical structure of the material. He also found that the sample was able to remember stimuli three hours old.
SOURCE: MIRA NEWS