(June 8, 2015) Researchers
at the University of Illinois at Urbana-Champaign have uncovered physical
mechanisms allowing the manipulation of magnetic information with heat. These
new phenomena rely on the transport of thermal energy, in contrast to the
conventional appication of magnetic fields, providing a new, and highly
desireable way to manipulate magnetization at the nanoscale.
“In our study, we make use of the fact that a heat current
passing through a magnetic material creates a separation of electron spins.
This process creates a current of magnetic dipoles that we use to manipulate
the orientation of a second magnetic layer,” said David Cahill, a Donald B.
Willett Professor of Engineering and head of the Department of Materials
Science and Engineering at Illinois. “The physics of separating spins with heat
currents is related to the operation of thermocouples and the thermoelectric
generators that power deep space probes. In those thermoelectric devices, a
heat current causes a separation of electrical charges. That separation of
electrical charge can then be used to measure a temperature or provide
electrical power.”