The Effect of Annealing Atmosphere on the Structure and Phase Formation of FePt/Cu/FePt Films Compositions
Keywords:Magnetic recording, Nanoscale films compositions, FePt, Phase transformations
Background. FePt based nanoscale films compositions with an ordered hard magnetic L10-FePt phase provide a perspective material for ultrahigh-density magnetic recording. An ordered L10-FePt phase is formed from a disordered A1-FePt phase during high-temperature annealing or films deposition on a heated substrate. However for practical application of these materials it is necessary to reduce the formation temperature of L10-FePt phase, and also to get preferred grain orientation structure.
Objective. The investigation of the annealing atmosphere influence on the formation of structural and phase compositions in FePt films with Cu intermediate layer.
Methods. Film compositions were obtained by magnetron sputtering, structure before and after heat treatment was investigated by X-ray diffraction methods.
Results. Using X-ray phase analysis it was found that regardless of the annealing atmosphere composition of in FePt(15 nm)/Cu(15 nm)/FePt(15 nm) nanoscale film composition the phase transformation A1-FePt→L10-FePtСu starts during heat treatment at temperature of 773 K. With a rise of annealing temperature up to 973 K the ordering degree of the ternary L10-FePtCu phase increases.Conclusions. It is established that annealing of FePt(15 nm)/Cu(15 nm)/FePt(15 nm) film compositions at 973–1073 K temperature range in Ar and N2 atmospheres leads to preferred texture formation of L10-FePtCu phase with preferred grain orientation in 001 direction. High temperature thermal treatment of FePt(15 nm)/Cu(15 nm)/FePt(15 nm) film compositions in Ar and N2 atmospheres leads to a sharp growth of grains.
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