Self-organization and FORC-based magnetic characterization of ultra-high aspect ratio epitaxial Co nanostrips produced by oblique deposition on an ordered step-bunched silicon surface

Abstract

Further development of microelectronics requires novel or improved technological approaches for device nanofabrication and functional properties characterization. In this paper, we studied the crystal structure and magnetic properties of epitaxial Co nanostrips with the average width of 32.6, 45.3, and 62.6 nm grown on a step-bunched Si(111)5.55 × 5.55-Cu/Cu surface. Technological conditions, under which the ultra-high aspect ratio (∼10) structurally solid, straight nanostrips of hcp-Co with crystallographic axis [0001] oriented along their long side can be grown, were determined. The dependence of the coercive force on the width of the nanostrips was demonstrated. Magnetization reversal through the transverse domain-wall nucleation and propagation in a Co nanostrip was defined with an analytical approach based on the Stoner-Wohlfarth model. Using the first-order reversal curve method, we analyzed the effect of nanostrip uniformity degree on magnetic behavior and the influence of the magnetostatic interactions on the coercive force of individual nanostrips.

Relaxation dynamics of magnetization transitions in synthetic antiferromagnet with perpendicular anisotropy

“…The geometrical meaning of the positive sign of P value (∂ 2 M/ (∂H A ∂H B ) is negative) is decrease of magnetic susceptibility at the point H B , which is proportional to the slope of tangent line to the FORC curve at the point H B , with increase of starting field H A . Expectedly, increase of starting field H A should result in reduction of magnetic susceptibility, because of reduction of difference between the magnetizations at the points H A and H B , as it was demonstrated in [26][27][28][29][30][31]. However, two small negative satellite spots are presented on the diagram (figure 9), additionally to the positive spots 1 and 2, discussed above.…”

“…Switching of the magnetic field to the values lying out of hysteresis loops did not stimulate magnetic relaxation in CoFeB bilayer, while same procedure causes relaxation in Pt/ Co bilayers. The values of relaxation parameters obtained by above described method can be compared with parameters extracted from first order reversal curve (FORC) map [26][27][28][29][30]. Although the data of FORC technique is obtained in sweeping magnetic field [31], while M(t) dependences were recorded in stationary magnetic field we will compare results below.…”

Step bunching with both directions of the current: Vicinal W(110) surfaces versus atomistic-scale model

“…From a technological perspective the patterning of surfaces is used in various experiments for the guided synthesis of nano-objects with reduced dimensionality -nano-dots, nanowires, etc. [21][22][23][24][25][26]. As noted the self-assembly of macro-scale steps under the influence of electro-migration is not limited to Si, one of the first observed such systems is probably the surface of tungsten, where systematic studies on the effect of electric fields on tungsten began with lamp filaments [27].…”

doFORC tool for calculating first-order reversal curve diagrams of noisy scattered data

“…The conjointly use of several experimental and modeling techniques is the current state-of-the-art in the quantitative FORC technique which already has offered profound physical insight in the study of many magnetic systems like the magnetic nanowire arrays, [12][13][14][15][16] magnetic wires, 17 antidote lattices, 18 magnetic bilayer ribbons, 19 nanostrips, 20 hard/soft bilayer magnetic antidots, 21 magnetic multilayer systems, 22,23 and even in molecular magnets at very low temperatures. 24 Many other such valuable studies could be mentioned in the last few years alone.…”