Ternary amorphous alloys for bubble domain applications

The drive field for bubble domain propagation in T‐bar devices is proportional to 4πMs. From the definitions of the characteristic length, l, and of Q it can be shown that 4πM is proportional to AQ, where A is the exchange stiffness.We have found that the magnetic properties of ternary amorphous systems of the type Gd‐Co‐X, where X is a nonmagnetic element, eg. Au, Cu, Mo can be fine tuned for bubble device applications. It is possible to lower A by magnetic dilution as well as adjust 4πMs by varying the Co/Gd ratio as in the binary system. Because the system is amorphous, we are not restricted by equilibrium solubility limits.