AMHERST, Mass. Scientists at the University of Massachusetts Amherst report that for the first time they have designed a much simpler method of preparing ordered magnetic materials than ever before, by coupling magnetic properties to nanostructure formation at low temperatures.
The innovative process allows them to create room-temperature ferromagnetic materials that are stable for long periods more effectively and with fewer steps than more complicated existing methods. The approach is outlined by UMass Amherst polymer scientist Gregory Tew and colleagues in the Sept. 27 issue of Nature Communications.
Tew explains that his group's signature improvement is a one-step method to generate ordered magnetic materials based on cobalt nanostructures by encoding a block copolymer with the appropriate chemical information to self-organize into nanoscopic domains. Block copolymers are made up of two or more single-polymer subunits linked by covalent chemical bonds.
The new process delivers magnetic properties to materials upon heating the sample once to a relatively low temperature, about 390 degrees (200 degrees Celsius), which transforms them into room-temperature, fully magnetic materials. Most previous processes required either much higher temperatures or more process steps to achieve the same result, which increases costs, Tew says.
He adds, "The small cobalt particles should not be magnetic at room temperature because they are too small. However, the block copolymer's nanostructure confines them locally which apparently induces stronger magnetic interactions among the particles, yielding room-temperature ferromagnetic materials that have many practical applications."
"Until now, it has not been possible to produce ordered, magnetic materials via block copolymers in a simple process," Tew says. "Current methods require multiple steps just to generate the ordered magnetic materials. They also have limited
|Contact: Janet Lathrop|
University of Massachusetts at Amherst