A. Pereira

Temperature-dependent magnetic properties of Ni nanotubes synthesized by atomic layer deposition

Highly-ordered and conformal Ni nanotube arrays were prepared by combining atomic layer deposition (ALD) in a porous alumina matrix with a subsequent thermal reduction process. In order to obtain NiO tubes, one ALD NiCp2/O3 cycle was repeated 2000 times. After the ALD process, the sample is reduced from NiO to metallic Ni under hydrogen atmosphere. Their magnetic properties such as coercivity and squareness have been determined in a vibrating sample magnetometer in the temperature range from 5-300 K for applied magnetic fields parallel and perpendicular to the nanotube axis. Ni nanotubes synthesized by ALD provide a promising opportunity for potential applications in spintronics, data storage and bio-applications.

General approach to the magnetostatic force and interaction between cylindrically shaped nanoparticles

In this paper we obtain analytical expressions for the magnetostatic interaction between cylindrical particles based on the assumption of a fixed uniform magnetization. Magnetostatic forces between the particles are established by these interactions. These general expressions allow the investigation of the magnetostatic interactions and forces between cylindrically shaped particles with different geometrical parameters like barcode-type magnetic nanostructures, multilayer nanotubes and nanowires, nanoparticles with modulated diameter, the ordering of nanoparticles on fluids, and others.

How do magnetic microwires interact magnetostatically

The magnetostatic interaction between two ferromagnetic microwires is calculated as a function of their geometric parameters and compared with those measured through magnetic hysteresis loops of glass-coated amorphous Fe%

Magnetic properties of Fe3O4 antidot arrays synthesized by AFIR: atomic layer deposition, focused ion beam and thermal reduction

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Tailoring the magnetic properties of ordered 50-nm- diameter CoNi nanowire arrays

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A soft/hard magnetic nanostructure based on multisegmented CoNi nanowires.

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Tailoring the magnetic properties of Ni81Fe19 thin films by varying their thickness

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Dewetting of Ni thin films obtained by atomic layer deposition due to the thermal reduction process: Variation of the thicknesses

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Reversal modes in asymmetric Ni nanowires

microwires. The hysteresis loops are characterized by well-defined Barkhausen jumps corresponding each to the magnetization reversal of individual microwires, separated by horizontal plateaux. It is shown that the magnetostatic interaction between them is responsible for the appearance of these plateaux. Finally, using the expression for the magnetostatic interaction is trivial to obtain the interacting force between microwires. Our results are intended to provide guidelines for the use of these microwires with technological purpose such as the fabrication of magnetic sensors.

Dewetting of Co thin films obtained by atomic layer deposition due to the thermal reduction process

Magnetic films of magnetite (Fe3O4) with controlled defects, so-called antidot arrays, were synthesized by a new technique called AFIR. AFIR consists of the deposition of a thin film by atomic layer deposition, the generation of square and hexagonal arrays of holes using focused ion beam milling, and the subsequent thermal reduction of the antidot arrays. Magnetic characterizations were carried out by magneto-optic Kerr effect measurements, showing the enhancement of the coercivity for the antidot arrays. AFIR opens a new route to manufacture ordered antidot arrays of magnetic oxides with variable lattice parameters.