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 CrRu/FePt/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

// 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 L1
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 degC</sub>