News from Nanotechjapan


Peltier Cooling and Heating in a Single Material without Junctions---Observation of Anisotropic Magneto-Peltier Effect in a Magnetic Material---

 National Institute for Materials Science (NIMS), Tohoku University, and Japan Science and Technology Agency (JST) announced on May 22, 2018 that a research group from NIMS and the university succeeded in observing anisotropic magneto-Peltier effect to enable thermoelectric cooling and heating in a single magnetic material without junctions. Details were published in Nature*.

 Interaction between electric and thermal current in metals and semiconductors generates electric power from waste heat (Seebeck effect) or heat flow by electric current (Peltier effect). Performance is described by coefficient of each effect, and the Peltier coefficient is defined as the ratio of the generated heat current to the applied electric current. Conventionally, junctions of two conductors with different Peltier coefficients have been believed to be indispensable for Peltier cooling or heating.

 The research group challenged and succeeded in demonstrating Peltier cooling and heating in a single magnetic material without junctions. By using active thermography techniques, the temperature change was successfully observed in a U-shaped ferromagnetic-nickel slab induced by this effect under applied magnetic field. According to the sample geometry, direction of the electric current changed from parallel to perpendicular against magnetic field at the corner of the slab.

 That is the observation of anisotropic magneto-Peltier effect in a magnetic material. It is expected to open a new way for thermal management technologies for electronic and spintronic devices.

*Ken-ichi Uchida, Shunsuke Daimon, Ryo Iguchi, and Eiji Saitoh, "Observation of anisotropic magneto-Peltier effect in nickel", Nature (2018), doi: 10.1038/s41586-018-0143-x; Published: 21 May 2018