Magnetic Properties of Ni/NiO Nanowires Deposited onto CNT/Pt Nanocomposites

Abstract

Several nanometer‐scale technological applications rely on the promising scenario of highly anisotropic magnetic materials. Bearing this in mind, we have studied the structure, magnetic properties, and interfacial exchange anisotropy effects of unique wires of Ni/NiO synthesized using carbon nanotubes as substrates. Structural analyses of these nanocomposites in correlation with magnetic measurements show that the crystalline NiO outer shells cause an enhanced exchange bias, providing an extra source of anisotropy that leads to their magnetization stability. These Ni/NiO nanowires, with a spin‐glass‐like behavior and with their magnetic moments in a blocked state over a wide temperature range that includes room temperature, should therefore inspire further study concerning the applicability of anisotropic structures.

Memory effect in weakly-interacting Fe 3 O 4 nanoparticles

“…They exhibit a saturated magnetization value of 55.1(1) emu/g under applied magnet field H a =15 kOe. The irreversibility shown in Figure 2(a) is strongly dependent on the magnitude of the applied magnetic field and is presumably associated with a slow relaxation process for an assembly of weak interacting nanoparticles, as discussed in a previous report 34 . 16 It can be seen that the influence of temperature on the saturation magnetization originates from the superparamagnetic characteristics in the Fe 3 O 4 nanoparticles.…”

Optically Active Magnetic Composites with Responsive Silica Shells

“…53 On the other hand, this fact may become very advantageous when working with these magnetic nanostructures because it permits combining the ability to harness the sizedependent properties of the nanostructures themselves with the possibility to tune the collective behavior due to interactions in between. 27,31,32 For the present case, these magnetic colloids offer remarkable coercivities that reach 135 and 30 Oe if cooling the sample to 5 K or measured at 300 K (Figure 4b). The reason for this behavior is also related to the distance between the magnetic cores.…”

Competing magnetic interactions and interfacial frozen-spins in Ni-NiO core-shell nano-rods

“…Although the magnetic suppression has been reported in oxygen-exposed Co clusters, 22 we noticed that it was not observed by Salgueiriño-Maceira et al in Ni-NiO core-shell nanowires deposited on Pt/carbon-nanotubes. 7 Compared to Ref. 7, our core-shell structure is more aligned and structurally uniform and is largely covered by a thicker NiO-shell (our NiO is larger than 6 nm, but the NiO-shell in Ref.…”