Tailoring of Perpendicular Magnetic Anisotropy in Dy13Fe87 Thin Films with Hexagonal Antidot Lattice Nanostructure

Abstract

In this article, the magnetic properties of hexagonally ordered antidot arrays made of Dy13Fe87 alloy are studied and compared with corresponding ones of continuous thin films with the same compositions and thicknesses, varying between 20 nm and 50 nm. Both samples, the continuous thin films and antidot arrays, were prepared by high vacuum e-beam evaporation of the alloy on the top-surface of glass and hexagonally self-ordered nanoporous alumina templates, which serve as substrates, respectively. By using a highly sensitive magneto-optical Kerr effect (MOKE) and vibrating sample magnetometer (VSM) measurements an interesting phenomenon has been observed, consisting in the easy magnetization axis transfer from a purely in-plane (INP) magnetic anisotropy to out-of-plane (OOP) magnetization. For the 30 nm film thickness we have measured the volume hysteresis loops by VSM with the easy magnetization axis lying along the OOP direction. Using magnetic force microscopy measurements (MFM), there is strong evidence to suggest that the formation of magnetic domains with OOP magnetization occurs in this sample. This phenomenon can be of high interest for the development of novel magnetic and magneto-optic perpendicular recording patterned media based on template-assisted deposition techniques.

Influence of nanoholes array geometrical parameters on magnetic properties of Dy–Fe antidot thin films

“…Therefore, thin films of antidot arrays are being intensely studied as candidates for many applications such as in high-density magnetic data storage, [4,5] magnetically active plasmonics, [6] microwave devices, [7] artificial spin ice, magneto-optic perpendicular recording patterned media [8] and magnetic biosensor applications [9]. Actually, the nanoholes can act as pinning centres for the magnetic domain walls, DW, and hinder their propagation through magnetic thin film.…”

“…Magnetic studies of amorphous REx-Fe(100-x) thin films indicate that, for the heavier rare-earth metals, these films show a ferromagnetic behaviour [24,27]. Recently, RE-TM nanostructures based on antidots have shown a strong potential for energy-assisted recording on nanometre-scale magnetic media, magneto-optic perpendicular recording patterned media based on template-assisted deposition techniques and ultrafast spintronic technology [8,[28][29][30] In this work, we pay special attention to the basic magnetic properties such as the magnetic anisotropy, Curie temperature, effective magnetic anisotropy energy, remanence and coercivity angular dependence, of Dy-Fe alloy antidot arrays by studying the effect of the geometrical parameters as they are, shape and size of nanohole, holes spatial ordering and antidot film thickness, on their magnetic properties. In addition, the influence of hexagonal ordering symmetry of nanoholes arrangement on the magnetothermal behaviour as compared to the continuous thin film samples has been investigated.…”

“…The deposition rate of the Dy-Fe alloy was around 0.1-0.15 nm s −1 . The experimental details about the deposition conditions have been already reported elsewhere[8,35].…”

“…A c c e p t e d M a n u s c r i p t instead to calculate the effective anisotropy coefficient, Keff, from the shape, magnetostatic and demagnetizing anisotropies, because of the inclusion of the arrays of nano-holes into the CTF[44].Thereby, it is possible to obtain an approximation of the anisotropy of the antidot arrays by using a simple and straightforward method, and thus easily infer on the magnetic properties of the material. Experimentally, the Keff can be obtained from the in-plane and out-of-plane loops, by considering all the macroscopic effects, such as the defects and the dislocations between the hexagonal domains of antidots[8,44] Where M is the magnetization, MS is the saturation magnetization and H is the applied magnetic field.…”

Dependence of the Magnetization Process on the Thickness of Fe70Pd30 Nanostructured Thin Film

“…Hexagonally ordered antidot arrays of Fe 70 Pd 30 alloy thin films formed by highly pure metal pieces of Fe (Goodfellow Limited, Cambridge, UK, 99.9% purity) and Pd (Ventron GMBH, Dortmund, Germany, 99.99% purity) were deposited on the NPAAT substrates by an ultra-high vacuum thermal evaporator (Edwards E306A, Manor Royal, Crawley, West Sussex, UK) at pressures below 10 −7 mbar, as described in [ 25 , 26 , 27 ], with a film thickness in the range of 20 nm ≤ t ≤ 80 nm (in steps of 20 nm). Continuous Fe–Pd alloy thin films (CTFs) were also deposited on a glass substrate at the same time as the antidot samples for comparison.…”