Low-temperature ordering of (001) granular FePt films by inserting ultrathin SiO2 layers

Abstract

L 1 0 granular FePt–SiO2 films with a (001) preferred orientation and well-separated grains of 5.14nm were obtained by depositing atomic-scale Fe∕Pt∕SiO2 multilayers (MLs) on glass substrates and subsequently annealing MLs at a temperature of 350°C. Large out-of-plane coercivity of 7700Oe and a high ordering factor of 0.83 were achieved. Alternate atomic-scale depositions promoted the formation of (001) textures. Furthermore, because of the low surface energy of SiO2 layers, SiO2 tended to diffuse into grain boundaries of FePt during annealing, which may accelerate diffusion of Fe and Pt atoms, resulting in the low-temperature ordering.

Low temperature ordering and high (001) orientation of [Fe/Pt/Cu]18 multilayer films

“…In the L10 phase, the atomic arrangement of Fe and Pt along c axis is like Fe/Pt multilayers. Since the perpendicular anisotropy of FePt films is strongly associated with the formation of the (001)-oriented L10 phase, the fabrication of FePt films by annealing Fe/Pt multilayers could not only effectively decrease the diffusion length of Fe and Pt atoms into L10 structure but also promote the perpendicular anisotropy [21]. On the other hand, there is very large interface energy in Fe/Pt multilayers.…”

“…We can see that the (001) and (002) superlattice peak positions of the films with Cu doping are higher than that of the FePt films without Cu doping. The previous research indicated that Cu in ordered FePtCu alloy is substituted into the Fe site in the L10 ordered FePt alloy; that is, the Cu is in the Fe plane of the L10 ordered FePt alloy through first-principle band calculations and ultraviolet photoelectron spectroscopy experiment [21]. The radius of Cu atom is smaller than that of Fe atom, which leads to decrease in the (001) plane spacing and the superlattice diffraction peaks of ordered phase shifted to the higher angles [26].…”

“…However, for practical application of FePt films as a perpendicular magnetic recording media, one basic requirement is to keep the (001) preferred orientation in FePt films. The alternate monatomic layer deposition of Fe and Pt is a very effective method for preparing L10 FePt films with high (001) orientation at low temperatures [20,21]. However, in these cases, the total thickness of the films exceeds 15 nm.…”

Magnetic properties and microstructure of (001) oriented Ag/FePt, Ag/FePt/Ag films

“…The hetero-epitaxial L1 0 FePt films were fabricated on single crystal substrate at high deposited temperature, for example, MgO substrate, or MgO, Cr/Pt, CrRu intermediate layer or Si substrate with suitable underlayer such as TiN, Ag [6][7][8][9]. The (0 0 l) textured (Pt/Fe) x films were typically prepared on amorphous substrates such as SiO 2 /Si, glass and subsequently annealing by rapid thermal process (RTP) [10,11]. The alternated deposition of (Pt/Fe) multilayer on MgO or glass substrate has been reported widely due to the lower ordering temperature.…”

In situ Grazing Incidence Scattering Investigations During Magnetron Sputtering Deposition of FePt/Ag Thin Films

“…Due to the high energy barrier, the transformation into the ordered L1 0 phase needs a subsequent annealing at temperatures above 500 8C to obtain the tetragonal distortion giving the strong ferromagnetic L1 0 phase. [9] In previous studies, we reported of low transition temperatures (T $ 350 8C) achieved using a special magnetron sputtering setup characterized by high amount of energetic atoms involved in the deposition that creates vacancies into the as-deposited films. [10] In this paper, we describe the fabrication of granular L1 0 -FePt/Ag films grown on SiO 2 (500 nm)/Si (001) substrates by means of sequential deposition of FePt and Ag at 400 8C.…”