Effects of B4C Addition on the Microstructure and Magnetic Properties of FePt-C Granular Thin Films for Perpendicular Magnetic Recording

Effects of B
₄
C addition on the microstructure and magnetic properties of FePt and FePt-C thin films have been studied. A high coercivity of 2.11 T with good squareness is achieved by B
₄
C addition. By analyzing the mechanism and different isolation effects of B
₄
C and C as segregants, a double-layer approach has been developed and a coercivity of 1.96 T is achieved with column-like FePt grains. The grain size and the size distribution are not deteriorated substantially compared with the single-layer case. These results indicate that addition of B
₄
C as segregant is beneficial for the modification of microstructure and magnetic properties.