Effect of Ag and Ti underlayer on the ordering in Fe/Pt multilayers

Abstract

The Fe/Pt multilayers with Ag,Ti,Cu,Cr,Pt and Ta underlayers were prepared by DC magnetron sputtering on the heated glass substrates.After vacuum annealing at d ifferent temperatures, the FePt thin films with L1０ ordering phase ( L1０-FePt) were obtained. Results showed that the Ag and Ti underlaye r prompt the ordering of FePt thin films, and the ordering temperature of FePt- L1０ phase is reduced by at least 150℃. It is also worth noting tha t the annealing time is shorter and the magnetic performance is excellent. The m agnetic performance of samples with Ag underlayer is not sensitive to temperatur e at relative higher annealing temperature, whereas the coercivity of samples wi th Ti underlayer decreases obviously when the annealing temperature is higher th an 500℃. After annealing at 400℃ for 20 min, the in-plane coercivity of sample s with Ag and Ti underlayer can be as high as 597kA/m, and 654kA/m， respectivel y, and the ratio of remanent magnetization to saturation magnetization reaches 0 .81 and 0.94, respectively, implying the potential of the films as future magnet ic recording media of ultrahigh density.