It has been proposed that Permalloy (Ni0.8Fe0.2) can be used as thin‐film magnetic bubble generator and sensor, and Au is a proposed electrical connector for input/output. We find that significant interdiffusion occurs to levels of 1–10 at.% for the diffusion couples Ni/Au, Fe/Au, and Permalloy/Au. We have determined 350°C solubility levels for all pairs for 1100‐Å films for annealing times from 10 to 2400 min. There was no degradation of electrical or magnetic properties of the Permalloy/Au system even at the highest levels of interdiffusion, indicating that it is ideally suited for a magnetic bubble metallurgy.