Magnetic and structural properties of single crystal Fe1−xZnx thin films

Abstract

Single crystal Fe1−xZnx thin films (x = 0 to 0.85) have been prepared on MgO(001) substrates by molecular beam epitaxy. Reflection high energy electron diffraction monitored the crystal quality of the films in situ and reveals a phase transition of the crystal structure from the α-Fe phase to primarily the Γ phase near a Zn concentration of 40%. Vibrating sample magnetometry shows a lack of any uniaxial anisotropy and a change in sign of the fourth order cubic magnetic anisotropy constant, K1, at a Zn concentration near 40%. The Fe1−xZnx samples maintain the high easy axis remanence and low coercivity of pure iron out to about 40% Zn, at which point the samples show a dramatic increase in coercivity, at least in part due to an increased roughness of the films, as the formation of the Γ phase becomes preferred.