Ion- Beam-Induced Damage In Thin Films of YBa sub 2 Cu sub 3 O sub (7-delta)

We have explored the effects of MeV ion irradiation on the electrical and structural properties of high quality, oriented thin films of YBa sub 2 Cu sub 3 O sub (7-delta). At relatively low ion fluences (-4x10 sup (13) ions/cm sup 2)), the superconducting critical current in the films is reduced by three orders of magnitude without substantial changes in T sub c or rho(RT). At higher ion fluences, superconductivity is destroyed and the films go continuously through the metal-insulator transition. Although the resistivity varies by more than an order of magnitude, the Hall coefficient changes very little. This implies that the metal-insulator transition is a result of a reduction in mobility rather than a drop in carrier density. A quantitatively consistent picture of the data can be obtained using a simple model which assumes that the primary effect of the bombardment is to generate point defects which are insulating.