Magnetic properties of ion-beam sputtered Cr3Fe-alloy films

Results of detailed magnetization study on ion-beam sputtered films of disordered Cr70Fe30 and Cr75Fe25 alloys-of varying thickness reveal strong departure from the bulk behaviour even for a film as thick as d = 470 nm: at this thickness, the Curie temperature T-C has dropped by roughly a factor of 2. In the range 9.4 nm less than or equal to d less than or equal to 470 nm, T-C alpha d(-1). This is contrary to Fe or Cr thin films where intrinsic magnetic properties vary with d only for ultra-tow thicknesses. Film stress in combination with a high degree of inherent chemical disorder, long-range ferromagnetic and antiferromagetic exchange interactions are thought to dominate variations of magnetic properties in the intermediate film thickness range. Hysteresis effects alone cannot account for the re-entrant spin glass-like behaviour observed at temperatures T much less than T-C. (C) 2002 Elsevier Science B.V. All rights reserved.