Cryogenic magnetic properties of secondary recrystallized thin sheet dysprosium

Secondary recrystallization was observed in 0.25mm thick dysprosium sheet having final cold reductions in the range of 40-60% prior to annealing at 1150°C in a dry helium atmosphere. X-ray and etch-pit studies revealed a predominant (0001)[ ] secondary recrystallized texture. Magnetization curves at 4.2 K and 77 K were in good agreement with (0001)[ ] single crystal magnetization curves. Coercivity measured from a peak induction of 3.1 T was 1.9 × 10³A/m at 77K, but increased to 16 × 10³A/m at 4.2K measured from a peak induction of 3.3 T. Square loop behavior was observed at 4.2 K, whereas low ratios of remanent magnetization to tip magnetization were observed at 77 K. The magnetization behavior is explained by domain models consistent with the single crystal magnetization curves, the temperature dependency of the (0001) magnetocrystalline anisotropy, and Egami\´s concept of an intrinsic wall coercivity in dysprosium at temperatures near 0 K.