[22p-B201-1~10] 10.1 Emerging materials in spintronics and magnetics (including fabrication and characterization methodologies)

▼ [22p-B201-6] Magnetic phase-transition-induced giant Thomson effect for thermoelectric cooling

〇(P)Rajkumar Modak¹, Masayuki Murata², Dazhi Hou³, Asuka Miura^1,8, Ryo Iguchi¹, Bin Xu⁴, Rulei Guo⁴, Junichiro Shiomi⁴, Yuya Sakuraba^1,5, Ken-ichi Uchida^1,4,6,7 (1.NIMS, 2.AIST, 3.ICQD, USTC, 4.The Univ. of Tokyo, 5.PRESTO, JST, 6.IMR, Tohoku Univ., 7.CSRN, Tohoku Univ., 8.Present-IREEAT, Kyushu Inst. Tech.)

Keywords:Magnetic phase transition, Thermoelectric cooling, Thomson effect

During past decades the fundamental physics, materials science, and applications of the Thomson effect remains to be investigated due to low magnitude of the Thomson coefficient τ in conventional materials. In this work, we report the observation of a giant Thomson effect in FeRh-based alloy where τ reaching -1,000 μVK^-1 around room temperature which is several orders of magnitude larger than it’s Seebeck coefficient S. This is achieved from the steep temperature dependence of S associated with the material’s phase transition. Using lock-in thermography technique, we further demonstrate that the Thomson cooling can be much larger than Joule heating in the same material even in a nearly steady state. Our results indicate that even substances with small S, which are not conventionally regarded as thermoelectric materials, can be used for thermoelectric conversion based on the Thomson effect if the temperature dependence of S is large revealing a new strategy for thermoelectric cooling.