Cu interfaced Fe/Pt multilayer with improved (001) texture, enhanced L10 transformation kinetics and high magnetic anisotropy

In the present work, enhanced L10 ordering kinetics with improved crystallographic texturing in [001] direction and high magnetic coercivity of about 6 kOe is observed in L10 ordered Fe(1-x)CuxPt films, after successive isochronal vacuum annealing of multilayer structure [(Fe(1-x)/Cux)/Pt]x10. Synchrotron grazing incidence x-ray diffraction (GIXRD) measurements, performed using area detector confirms the onset of L10 ordering at 200 degrees C and presence of high degree of ordering at 300 degrees C. In-plane and out-of-plane GIXRD measurements validates texturing of magnetic easy axis [001] in out of film plane direction. Enormous increase in magnetic coercivity is observed from MOKE measurements in L10 ordered state. Lower ordering temperature with enhance (001) texturing and high magnetic coercivity is desirable for potential device applications of FePt. Effect of Cu and annealing temperature on structural and magnetic properties is investigated systematically in Fe(1-x)CuxPt films. Structural investigation discloses that lattice distortion in L10 ordered state caused by Cu addition and high interfacial energy associated with initial multilayer structure drives faster interdiffusion. Both of these aspects collectively work for FCC to FCT transformation, hence results in enhanced kinetics and texturing effects of L10 FePt.