Magnetic Properties of Amorphous GdCo Films

We have measured the spontaneous magnetization of amorphous Gd1−xCox films with 0.36 ≤ x ≤ .96, in the temperature range 4.2 – 600 K, and compare the properties of the films with those of six ordered Gd–Co compounds which form within this composition range. Like the crystals, the films appear to be collinear ferrimagnets, with Gd and Co spins ordered antiparallel, and display Gd‐dominated, compensated, and Co‐dominated magnetization curves as the Co concentration is increased. A compensation point is present over a wider range of compositions in the films than in crystals. There is a range (roughly 0.6 < x < 0.8) in which TC and the Co moment are greater in the films than in the crystals, in contrast to previous experience with disordered magnets. These changes in the magnetic properties of the Co atoms can be qualitatively accounted for as an effect of charge transfer.