Compositional Microstructure and Micromagnetics of Co-Based Thin Film Media

Abstract

AbstractElemental segregation of CoCrTa and CoCrPt thin films for longitudinal and perpendicular media is investigated using high spacial resolution transmission electron microscopes equipped with compositional analysis facilities. Strong Cr segregation exceeding 20 at% within 1.5-2 nm width is observed along the grain boundaries for both types of CoCrTa films prepared at elevated substrate temperatures. Weaker Cr segregation is observed along the grain boundaries of the longitudinal and the perpendicular CoCrPt films. The strong Cr segregation at grain boundaries is related with the small magnetic cluster size and the low media noise characteristics of CoCrTa thin film media. The Cr content inside the grain is several % lower than the average composition of the CoCrTa films. The magnetocrystalline anisotropy constants(Ku) for different Cr compositions are determined using single crystalline thin film technology to discuss the thermal stability of recorded information.