Research ArticleCONDENSED MATTER PHYSICS

Nonreciprocal thermal transport in a multiferroic helimagnet

See allHide authors and affiliations

Science Advances  30 Sep 2020:
Vol. 6, no. 40, eabd3703
DOI: 10.1126/sciadv.abd3703
  • Fig. 1 Magnetic and phononic states of multiferroic TbMnO3 and experimental setup for nonreciprocal thermal transport.

    (A) Illustration of magnetic structure in a magnetic field H parallel to the a axis. (B) Expected acoustic phonon modes along the b axis at H = 0 (solid lines) and finite H (dotted lines). (C) Illustration of the experimental setup for nonreciprocal thermal transport measurement. The distance between two thermometers is 1.05 mm. The sample thickness and width are 0.4 and 1.15 mm, respectively.

  • Fig. 2 Temperature dependences of magnetic, electric, and thermal transport properties of TbMnO3.

    (A) Temperature dependence of magnetization at H = 0.5 T parallel to the c axis. Inset shows the low-temperature and large magnetization region. (B) Temperature dependence of electric polarization parallel to the c axis at H = 0. (C) Temperature dependence of thermal conductivity at H = 0. The vertical dashed lines indicate the magnetic transition temperatures. The kink temperature in the magnetization is slightly higher than that in electric polarization around 27 K, owing to the application of the magnetic field.

  • Fig. 3 Nonreciprocal thermal transport at 4.2 K.

    (A) Magnetization curve along the a axis at 4.2 K. (B and C) Magnetic field variation of thermal conductivity at 4.2 K for H || a. In (C), the thermal conductivity scale is magnified around κ(H)/κ(0) = 0.83. (D) Magnetic field dependence of thermal nonreciprocity Δκκ for ±P and H || a at 4.2 K. (E) Averaged thermal nonreciprocity Δκav/κ as a function of thermal current density at 4.2 K. The error bars are estimated as the error of thermal conductivity from the temperature fluctuation during the measurement divided by the square of number of averaged data points. Black solid lines are merely guides for the eyes.

  • Fig. 4 Temperature dependence of nonreciprocal thermal transport.

    (A to H) Magnetic field variation of thermal nonreciprocity Δκ/κ for ±P and H || a at various temperatures. (I) Temperature dependence of averaged thermal nonreciprocity Δκav/κ for ±P. The error bars are estimated as the error of thermal conductivity from the temperature fluctuation during the measurement divided by the square of number of averaged data points. Solid lines are merely guides for the eyes.

Supplementary Materials

  • Supplementary Materials

    Nonreciprocal thermal transport in a multiferroic helimagnet

    Yuji Hirokane, Yoichi Nii, Hidetoshi Masuda, Yoshinori Onose

    Download Supplement

    This PDF file includes:

    • Fig. S1

    Files in this Data Supplement:

Stay Connected to Science Advances

Navigate This Article