Reduced Susceptibility of Irradiated Palladium

The ac susceptibility of thin PdFe films has been measured before and after low-temperature irradiation with inert noble gases by using a newly developed susceptometer. The disorder introduced by the irradiation causes a reduction in both the Curie temperature by a factor of 2 and the Curie constant by a factor of about 7. From this result it is calculated that the low-temperature irradiation reduces the susceptibility of the Pd host by more than an order of magnitude, thus explaining the recently observed superconductivity in irradiated Pd.