Chemically deposited CuCo granular films: an alternative route to GMR

The magnetic behaviour of a Cu0.75Co0.25 thin film produced by chemical deposition has been investigated over the temperature range 5 to 300 K and in magnetic fields of up to 5 T. The film exhibits either hysteretic or reversible behaviour depending upon the temperature. This is interpreted as being due to the presence of small particles of fcc Co in the non-magnetic matrix, which exhibit superparamagnelism at higher temperatures with a maximum blocking temperature of 20 K. After anneal at 400 °C, the sample is ferromagnetic at room temperature. The variation of the GMR on anneal is also investigated.