Anomalous Thermal Resistance Between Sintered Copper Powder and DiluteHe3-He4Solutions

The thermal resistances between seven samples of sintered copper powder and a nearly saturated dilute ${\mathrm{He}}^3$-${\mathrm{He}}^4$ solution were measured between 14 and 200 mK. All samples showed the anomalously high thermal resistances seen in metal foils, and the values are in semiquantitative agreement with recent calculations of Seiden. Reproducibility of samples was found to be excellent and oxide layers formed at room temperature had no detectable effect.