A magnetic material comprises 50-80 wt % of Cobalt, 9-15 wt% of Nickel, 10-25 wt% of Rhenium, 0.1 to 2.0 wt% of Phosphorus, and 5-10 wt % of Tungsten or Platinum. It can be formed as a layer having good vertical magnetic properties (e.g. when magnetised it can provide a high magnetic field strength in the direction perpendicular to the plane of the layer). The layer preferably has a thickness of above 1 .mu.m. It can be formed by electroplating. The layer is useful for inclusion in a MEMS device.