3$\omega$ Thermal Conductivity Measurement of La$_{2-x}$Sr$_{x}$CuO$_{4}$ in pulsed high magnetic field

It is difficult to study the normal state behavior of High T$_{C}$ superconductors below T$_{C}$, because high magnetic field is required to suppress the superconducting state. National High Magnetic Field Laboratory in Los Alamos has a high magnetic field facility up to 75T using pulsed magnets. Users can perform a variety of measurements including resistivity, Hall effect, magnetization, photo-luminescence, and specific heat. Recently, we developed thermal conductivity measurement in high magnetic field utilizing the 3$\omega $ technique. La$_{2-x}$Sr$_{x}$CuO$_{4}$ is reported to have enhanced thermal conductivity in the superconducting state. By applying magnetic field, this enhancement is reduced. The intriguing feature is that the temperature T$_{K}$ below which thermal conductivity is reduced by magnetic field is higher than T$_{C}$. Furthermore, it was shown that small substitution of Cu by Zn prevents this reduction. In this talk we will report the recent thermal conductivity data of La$_{2-x}$Sr$_{x}$CuO$_{4}$ in high magnetic field to shed lights on this subject, by totally suppressing the superconducting state.