THERMAL CONDUCTIVITY AND ELECTRICAL RESISTIVITY MEASUREMENTS OF EUO ACROSS THE CURIE TEMPERATURE IN A MAGNETIC FIELD.
SOUTH DAKOTA SCHOOL OF MINES AND TECHNOLOGY RAPID CITY DEPT OF PHYSICS
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The thermal conductivity K of a hot-pressed sample of EuO 90 EuO, 10 Eu2O3 was measured in the temperature range 60-300K using the linear absolute method. K falls off sharply as the temperature goes below 90K, and then rises again by 60K. The dip is not symmetric but its sides intersect at 69K. K was also measured in a longitudinal magnetic field of 100 gauss in the temperature range 60-78K. A dip at 69K was again observed however, in the magnetic field K fell off less sharply and the dip was much shallower. The electrical resistivity r was also measured. In the absence of the magnetic field r deviated by less than 1 from a value of 0.040 ohm-cm over the entire temperature range 60-300K. Application of the magnetic field resulted in changes of r of less than 2 throughout this same temperature range. The downward dip in the thermal conductivity at the ferromagnetic-paramagnetic transition temperature of 69K can be qualitatively understood in terms of critical scattering of phonons by critical fluctuation in the energy density of the spin system. Author
- Electricity and Magnetism
- Solid State Physics