One way to change the properties of a material is to stretch it just a wee bit, so its atoms are farther apart but the bonds between them don't break. This extra distance affects the behavior of electrons, which determine whether the material is an insulator or a conductor of electricity, for instance.
But for an important class of complex oxide materials, stretching doesn't work so well; they're as brittle as ceramic coffee cups and would break.
Scientists at the Department of Energy's SLAC National Accelerator Laboratory and Stanford University have now found a way around this problem for a complex oxide known as LCMO. They created a super-thin, flexible membrane from the normally brittle material, used micromanipulators to stretch it on a tiny apparatus and glued it in place to preserve the stretch.
By applying gentle heat to melt the glue, they could release and stretch the same transparent membrane again and again and watch it flip from being an insulator to a conductor and back again. Stretching also changed its magnetic properties.
"We can really stretch and strain these things dramatically, by up to 8%," said Harold Hwang, a professor at SLAC and Stanford and an investigator with the Stanford Institute for Materials and Energy Sciences (SIMES). "This opens a whole new world of possibilities that will have an impact beyond this particular study."
The research team reported its findings in Science today.
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