Magnetic properties at 77 K of thin sheet Gd/sub x/Dy/sub 1-x/ alloys

The direct current magnetic properties of six Gd/sub x/Dy/sub 1-x/ (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) alloys were characterized at 770K. These alloys were cold rolled in three stages from an initial thickness of 1.5 mm to a final thickness of 0.25 mm and annealed to promote primary recrystallization and grain growth. The sheet-type materials were wound in the form of toroids 26 mm in diameter and submerged in liquid nitrogen for magnetic testing using a Yewtec hysteresigraph. Only pure Gd could be magnetically saturated in a maximum magnetic field of 12 x 104 A/m. The progressive substitution of dysprosium for gadolium produced noteworthy changes in the shape of the magnetization curves and the bulk coercivity behavior. For Gd-rich alloys (x = 1.0, 0.8, 0.6), there were no discontinuities in the magnetization curves to a peak magnetizing field of 12 x 104 A/m; coercive forces in these alloys rose linearly from 120 A/m to 6000 A/m. The coercive force behavior reflects the increase in magnetic hardness with increasing Dy, and may also indicate that the bulk magnetocrystalline anisotropy of these alloys decreases with increasing Gd content. On the other hand, in Dy-rich alloys (x = 0.4, 0.2, 0.0) the coercive force was nearly constant at a value of 8400 A/m indicating that the magnetocrystalline anisotropy was independent of Gd content