University of Pennsylvania researchers have developed a method for creating phase change materials (PCMs), which could lead to more efficient and faster memory storage devices.
The use of PCMs in memory storage devices has been limited by the fact that the mechanics of the phase change is still somewhat mysterious. The phases that PCMs switch between are different arrangements of their internal atomic structure. The two phases provide different levels of resistance to electrical current, which is why they are useful in memory storage. Previously, the only way to switch between the crystalline phase and the amorphous stage involved heating, which enables the atoms to move out of their lattice positions as the material briefly melts, followed by rapid cooling, which solidifies the material into the amorphous phase without allowing the atoms to recrystallize.
"Now we have shown that there is a way to achieve this transition without melting the material," says Pennsylvania professor Ritesh Agarwal.
The method involves using short electrical pulses to gradually induce disorder in the material until it amorphizes. The method enabled the researchers to observe the phase change as it happened using a high-resolution transmission electron microscope.
From Penn News
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