Low-Temperature Magnetic Remanence, Molecular Field, and Approach to Saturation of Holmium Metal

Abstract

Magnetization approaching absolute magnetic saturation has been achieved for polycrystalline holmium metal. At 1.3°K and 70 000 gauss, the magnetic moment is approaching 4.0 Bohr magnetons per atom of holmium in contrast to the 10 Bohr magnetons per atom expected on the basis of the spectroscopically determined quantum numbers. The actual results are explained on the basis of crystalline electric field splitting of the ground term of holmium and application of the Pauli exclusion principle. In the liquid helium range, there is a pronounced hysteresis; i.e., the moment at 10 000 gauss is 50% higher in decreasing fields than in increasing fields. The remanence is 0.22 Bohr magneton per atom of holmium at 4.2°K and 0.42 Bohr magneton per atom at 1.3°K. A sample motion technique was used to measure the magnetic moment of the 5-gram sample. The equipment was calibrated with iron and nickel.