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.

Self-assembly of magnetic Ni nanoparticles into 1D arrays with antiferromagnetic order

“…Collective magnetic states are experimentally well known in nanoparticle ensembles although the origin of the interaction is often unclear [44][45][46][47][48]. Here, a first fingerprint of AF order in the nanochain sample is associated with the FC branch of the magnetic moment m versus T data.…”

Interplay of chemical structure and magnetic order coupling at the interface between Cr2O3 and Fe3O4 in hybrid nanocomposites

“…Additionally, a second option can consider a spin-glass, given the nanoparticulated morphology of the nanocomposites. 32 On the other hand, though clear that there is an exchange interaction between the two oxides, not only because of the shift of the hysteresis loop after field cooling, but also because of the increase in coercivity, we can point out two main reasons for the very low value of the exchange bias field H E . First we can consider the fact of having a 3D interface between the two oxides, which averages out the exchange coupling and consequently the value of H E , and second, we also have to take into account the postsynthetic metallic cation exchange at the interface between the two oxides, which can also decrease the value of H E .…”

Exchange bias in single-crystalline CuO nanowires

“…The ZFC curve shows a clear maximum at T B ϳ19 K and an evident separation from the FC curve below T B , suggesting a SG-like behavior at low temperatures. 9,10,16 Such behavior can be attributed to uncompensated surface spins in the nanowires, which result frozen due to the applied field. In our case, T B is much lower than T N .…”