Giant spin Seebeck effect in a non-magneticmaterial

Center for Emergent Materials
The Ohio State University
Giant spin-Seebeck effect could provide power from waste heat
spin/phonon effect increased 1000-fold in semiconductor with strong spin-orbit interactions
An OSU research team has been studying the
interaction between heat and magnetic materials. One
such effect, called the spin-Seebeck effect, allows for
heat to move magnetic information. The magnetic
information is then converted into electrical power. The
OSU team previously observed the effect to occur in a
magnetic semiconductor but it produced small
electrical power. The effect can be maximized when
heat particles, called phonons, drag the magnetic
moments. This past year, the OSU team discovered that
the effect is 1000 times larger in a material that
contains no magnetism. This strange result is explained
since the electrical charges in the material can also
have magnetism due to a property called spin. The
effect is strong enough that the OSU team is now Co
examining if it might be useful for converting heat into
electrical power based on this spin effect. Their
research is now focused on determining what
properties allow heat/magnetism/spin effects to
become largest and then producing materials that
display those effects.
(left) When heat causes atoms to vibrate in a crystal,
those vibrations can rotate the magnetism of
electrical charges, called spin. (right) The spin is
then converted into electrical power using a metal
Roberto Myers (Materials Science Engineering),
Chris Jaworski, Joseph Heremans (Mechanical
Engineering), and Ezekiel Johnston-Halperin
An NSF Materials Research Science and Engineering Center (MRSEC)
Supported under Award Number DMR-0820414