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In this paper, we study the magnetization behavior in Co40Fe40B20 nanodisks with Dzyaloshinskii-Moriya interaction, which is induced by a Pt layer. The known giant perpendicular magnetic anisotropy (PMA) in thin films elaborated from this kind of materials improves the topological structures nucleation. Our work consists in investigating the skyrmions apparition and stability in amorphous CoFeB nanodisks. The detected skyrmions are not spontaneously nucleated. Their nucleation is induced by an applied external field. We also study reversal magnetization of CoFeB and we elucidate skyrmions nucleation and annihilation.

In this paper, a calculation model is proposed to measure magnetocaloric effect (MCE) and relative cooling power (RCP) in composites based on magnetic materials underscoring a giant MCE at room temperature. The two composite materials targeted are Gd-Gd5Si2Ge2 and MnAs- Mn 1 + δ As 0.9 Sb 0.1 due to their high magnetic entropy change ΔSM over 270–300 K and 280–320 K. Our selected composites could give a larger RCP value among existing magnetocaloric materials for magnetic refrigeration in the temperature range of 280–300 K which is desirable for ideal Ericsson-cycle magnetic refrigeration. The excellent magnetocaloric properties of these two magnetic composites make them attractive for active magnetic refrigeration at room temperature.

Nanometric spin structures such as skyrmions are covering a large area of applications related to new technologies. In this paper, we carry out a computational study on magnetic skyrmions behavior in Pt/CoFeB/Ru/CoFeB antiferromagnetic-exchange coupled systems. We aim to explore the possibilities of skyrmions nucleation in such multilayer. We demonstrated that skyrmions could be hosted in such system under specific conditions. We also studied the in-plane and out-of-plane reversal magnetization processes for these magnetic multilayers in order to check the skyrmion behavior under magnetic field loops.

The effective field theory with correlations has been employed to study the hysteresis behavior of a ferromagnetic and ferrimagnetic three-walled mixed-spin Ising nanotube with an inner hexagonal vacancy. The effects of different exchange couplings, single-ion anisotropies, and temperature on the hysteresis loops of the sublattices and the overall system are attentively discussed. Multiple hysteresis loops have been observed in the system under certain physical hamiltonian parameters. It is found that the remanences and the coercivity of the sublattices and the system are strongly affected by the temperature, the exchange couplings, and the anisotropy. A satisfactory agreement can be qualitatively achieved by comparing our results with experiments and theoretical studies. Amazing behaviors are revealed thanks to the geometry, the different spins, and the multiple interactions involved in the system.

In this work, the magnetization states under the spin-transfer switching effect are investigated in a nanopillar device composed of a half-metallic Heusler Co 1.5 F e 1.5 G e alloy with a four-fold in-plane magnetocrystalline anisotropy. A comparative study with a half-metallic Heusler alloy of Co 2 F e A l 0.5 S i 0.5 and a typical material of Fe is realized by numerically solving the Landau-Lifshitz-Gilbert (LLG) equation with the Spin-Transfer Torque (STT) contribution, using micromagnetic simulations. Our ultimate goal is to elucidate the origins of the intermediate state (IS) that occurs during magnetization switching by deeply examining the effects of magnetocrystalline anisotropy and shape anisotropy on the magnetization states through analyzing and comparing various switching processes. Our simulation results showed that the magnetization switching via a single-step under low current densities is possible at certain critical cross-sectional dimensions of the ellipse that are adjusted to increase the demagnetization field against the four-fold in-plane magnetocrystalline anisotropy. As well, we provided in this paper a set of appropriate geometric dimensions which allow the magnetization to reverse via a single-step by overcoming IS with minimal spin-polarized current densities.

Magnetic skyrmions have attracted a great deal of interest in the last decades. They are widely used for many spintronic applications. In this manuscript, we study by micromagnetic simulation the emergence of a hexagonal Neel-type skyrmion lattice in a square thin film of CeFeB. We specifically examine the formation and annihilation of the skyrmion lattice. Moreover, we show the decrease of the skyrmion sizes with the increase of the magnetic field, while the lattice parameter remains unchanged during this rise.