An international team of researchers sheds new light on how certain complex materials can be altered for different purposes without having to produce new materials, effect chemical change on their concentration or even apply external pressure through magnetic fields.
In a study featured in the journal Proceedings of the National Academy of Sciences, scientists from Louisiana State University (LSU), the University of Florida (UFL), Fudan University and the Collaborative Innovation Center of Advanced Microstructures in China studied the properties of complex materials, especially when subjected to specific pressures, temperatures and magnetic fields.
The researchers made use of a process known as electronic phase separation to manipulate manganite, which is a steel gray mineral that is typically used to manufacture the magnetic hard discs often found in computers. The team then produced holes (antidots) in the thin manganite films. They found that the edges of these antidots on the films were magnetic.
Ward Plummer, a physics professor at Louisiana State University and co-author of the research, explained that their work was made possible because of the discovery of the antidots' magnetic edges. He said that nobody had ever observed this occurrence before.
The magnetic phase state found on the antidots' edges helped raise the manganite film's metal-to-insulator phase transition temperature. Plummer and his colleagues successfully replicated this occurrence through simulations.
Jian Shen, head of Fudan University's physics department and co-author of the research, said that other researchers have tried either to raise the antidots' temperature and reduce its operating field, or alter its substrate or chemical composition. He said that the new approach using antidots is useful to their research.
Plummer pointed out that what they would really like to do is to raise the temperature of the antidots above room temperature to allow them to manipulate the materials through the use of a magnetic field.
The recent study is part of Shen and Plummer's on-going collaboration. They began their work together at the Oak Ridge National Laboratory in 1998. The two scientists worked on manganite systems that featured low magnetic fields in high temperatures.
The collaborative project continues through funding provided by the Department of Energy.
