When you think of South Dakota you generally think of Mount Rushmore and, maybe, nuclear missiles. However, [Simeon Gilbert] will make you think of semiconductors. [Simeon], a student at South Dakota State University, won first place at the annual Sigma Xi national conference because of his work on a novel magnetic semiconductor.
The material, developed in collaboration with researchers from the nano-magnetic group at the University of Nebraska-Lincoln, is a mix of cobalt, iron, chromium, and aluminum. However, some of the aluminum is replaced with silicon. Before the replacement, the material maintained its magnetic properties at temperatures up to 450F. With the silicon standing in for some of the aluminum atoms, the working temperature is nearly 1,000F.
Although many magnetic materials (like magnetite) are also semiconductors, their properties are not generally comparable to traditional semiconductors like silicon. This has led to more research on combining magnetic materials and semiconductors to produce semiconductors that also exhibit ferromagnetism.
In theory, a control device made out of magnetic semiconductor would allow switching by charge carriers (as in a traditional transistor) but also provide control of spin state and polarization. A practical “spin transistor” could allow higher storage densities and lower power for non-volatile memory. Higher temperature devices can also reduce cooling requirements which can have important size and power savings.
Too bad that just when [Dan Maloney] finally got magnets figured out, [Simeon’s] going to add a new kind of material. If you haven’t run into the idea of spin transistors before, you might enjoy the video from National Cheng Kung University, below.