Tb<i>x</i>Nd<i>y</i>(FeCo)1−<i>x</i>−<i>y</i>: Promising materials for magneto-optical storage?

Abstract

A systematic study of the pseudoternary system TbxNdy(FeCo)1−x−y is presented focusing on key parameters for magneto-optical storage applications. For compositions with perpendicular anisotropy at room temperature (x&amp;gt;0.08; 0.4&amp;gt;z+y&amp;gt;0.15) the Kerr rotation (λ=633 nm) increases with FeCo concentration for a given x/y ratio and increases also with the Nd concentration for a given FeCo concentration. The latter effect is more pronounced at λ=420 nm than at λ=800 nm. Room-temperature compensation is found at x=0.2 for all of these compounds indicating a Nd moment parallel and, in magnitude, similar to the FeCo moment. The high-temperature magneto-optical measurements revealed a significant lowering of the anisotropy constant at elevated temperatures with Nd concentration, which leads to a loss of square loops already 100 K below TC for certain compounds.