Ferromagnetism in DyRh and DyRhX (X = Fe, Ni, Co, Gd) thin films

Abstract

In an effort to achieve large high-field magnetization and increased Curie temperature, polycrystalline DyRh, (DyRh) 95 X 5 and (DyRh) 85 X 15 (X = Fe, Co, Ni, Gd) thin films have been prepared via ultra-high vacuum DC co-sputtering on SiO 2 and Si wafers, using Ta as seed and cap material. A body-centred cubic CsCl-like crystal formation (B2 phase) was achieved for DyRh around the equiatomic equilibrium, known from single crystals. The maximum in-plane spontaneous magnetization at T = 4K in fields of µ 0 H = 5T of was found to be µ 0 M S,4K = (1.50 ± 0.09)T with a ferromagnetic transition at T C = (5 ± 1)K and a coercivity of µ 0 H C,4K[D] = (0.010 ± 0.001)T (at T = 4K) for layers deposited on substrates heated to 350°C. Samples prepared at room temperature exhibited poorer texture, smaller grains and less B2-phase content; this did impact on the Curie temperature which was higher compared to those layers with best crystallisation; however the maximal magnetization stayed unaffected. Ferromagnetic coupling was observed in ternary alloys of DyRhGd and DyRhNi with an increased Curie temperature, larger initial permeability, and high-field magnetization which was best for (DyRh) 85 Gd 15 with µ 0 M S,4K[Gd15] = (2.10 ± 0.13)T.DyRhFe and DyRhCo showed antiparallel coupling of the spontaneous magnetic moments.

A review of high magnetic moment thin films for microscale and nanotechnology applications

“…[389][390][391][392] However, among the latter, one ternary alloy system was found in 2014 which showed signs of FM coupling: DyRhNi (more specifically: the (DyRh) 85 Ni 15 composition). 393 Although its saturation magnetisation is only l 0 M S ¼ 1.7 T and its Curie temperature only T C ¼ 22 K, excluding it from considerations of an FeCo alternative, it is worth being highlighted for its remarkable softness and for being one of only two reported cases of parallel RE-TM coupling in an alloy (the second one is discussed in Section II G 2). There is yet no in-depth investigation of its magnetic structure and what precisely causes its peculiar behavior.…”

Magnetic properties tailored by inserting ultrathin Cr layer in Gd/Ni80Fe20film

“…Magnetic thin films/multilayers composed of rare-earths (RE) and transition-metals (TM) are of great importance for both fundamental research and technological applications in magn etic sensors, magnetic storage media, magnetic recording heads and spin-torque nano-oscillators, stemming from their dissimilar properties [1][2][3][4][5]. In these, the Curie temperatures (T c ) of RE can be improved and the spin-orbital coupling of magnetic films can be modulated.…”