Bulk nanocrystalline gadolinium metal was prepared using spark plasma sintering (SPS) and subsequent annealing process. The SPS Gd metal had a single phase with a mean grain size of about 10nm. A pressure-induced C-axis crystal texture was found in the SPS Gd sample. With the decrease of Gd grains from micrometer to nanometer range, the Curie temperature TC decreased by 10.7K and the magnetic moment per Gd atom at 5K dropped noticeably from 7.81μB to 6.31μB. These results indicate the remarkable influence of the nanostructure on the magnetism of Gd due to the finite size effect.

The structure and magnetic properties were studied for bulk nanocrystalline dysprosium (Dy) metal prepared by spark plasma sintering method. All the as-prepared samples have hexagonal close packed structure. A decrease in grain size results in remarkable changes in magnetic ordering temperature of the nanocrystalline Dy metal. At 5K, the magnetization drops by 3.35%, and the coercive force increases by three times for nanocrystalline Dy compared to those of coarse-grained bulk Dy sample. These results indicate the remarkable influence of the nanostructure on the magnetism of Dy due to finite size effect.

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