The thermal conductivity and the magneto-thermal resistance effect of CMR material La2/3Ca1/3MnO3
Fan Yu and Jirong Sun
The thermal conductivity of manganese perovskite La2/3Ca1/3MnO3 polycrystal sample was measured from 150 K to 360 K. The phonon contribution to the total thermal conductivity is dominant. Although the electrical contribution is very small, the lattice transport is closely related to the charge transport. The experimental results show that the variations of the thermal resistivity with temperatures are similar to the variations of electrical resistivity under different magnetic fields, and furthermore, the variations of the magneto-thermal resistance (MTR) are similar to the magnetoresistance (MR). The MTR effect near Curie temperature TC, namely that the thermal resistance decreases with the magnetic field increasing, will take place simultaneously after the CMR effect, but the magnitude of MTR is obviously lower than the MR value. The observed results in the manganese perovskite indicate that both the MTR and the MR effects may be governed by the same local physics, all owing to the substantial increase in the volume fractions of ferromagnetic metal domains.
Keywords: Thermal conductivity, electrical resistivity, magneto-thermal resistance, colossal magnetoresistance, electrons, phonons.