Effects of CrRu underlayer and CrRu capped layer on the microstructure and magnetic properties of FePt films

The magnetic properties and microstructure of CrRu/FePt bilayer and CrRufFePt/CrRu trilayer deposited by dc magnetron sputtering on preheated natural-oxidized Si (100) wafer substrates were studied. It is found that both the in-plane coercivity ([Hc.sub.//]) and grain size of the FePt film increase with increasing the thickness of CrRu underlayer. The [Hc.sub.//] value of the FePt film is further increased but the grain size is decreased as adding a CrRu capped layer on the FePt film. The granular L[1.sub.0] FePt nanoparticles with in-plane coercivity of 2300 Oe and isolated uniform size of 6.61 nm are achieved from the CrRu(15 nm)/FePt(25 nm)/CrRu(4 nm) film deposited at a low substrate temperature of 350[degrees]C. Index Terms--CrRu/FePt bilayer, CrRu/FePt/CrRu trilayer, in-plane coercivity, magnetron sputtering.