Measurements on Chromium Potassium Alum below 1°K

Measurements of the real part, ${\chi }^{\prime }$, and imaginary part, ${\chi }^{\prime \prime }$, of the ac susceptibility, the ballistic susceptibility, and the remanence were made on chromic potassium alum in the range of temperature below 1°K. The results provide confirmation of earlier measurements in the region above 0.1°K, but show some discrepancies at lower temperatures, particularly in the behavior of ${\chi }^{\prime \prime }$. Some absolute temperature determinations, in the region of the "Curie point," were also made and these are of particular interest in view of wide discrepancies between such measurements made at Oxford and at Leiden.