Atomic-Scale Description of the Magnetic TiN|FeCo Multilayers

Motivated by the experimental findings of Wolff et al., we investigated the TiN|FeCo multilayers at the atomic scale. Four different models were employed to investigate the interface, considering both Fe and Co surface terminations of the FeCo compounds. The interface formation energy formalism was employed to study the thermodynamic stability of these models. The results show that an interface mediated by Co atoms is most likely to appear in the experiment. Also, the Fe surface termination is more viable than a Co surface termination. The magnetic moments of Co at the interface are 1.48 μB/atom, which denotes a decay compared to bulk (1.76 μB/atom). Besides, Ti acquires a very small induced magnetization of -0.05 μB/atom. Our proposed atomistic model of the TiN|FeCo multilayer system fits perfectly with the structure obtained in experiments, and it is a step forward in the theoretical-experimental design of wear-resistant coatings with outstanding magnetic and mechanical properties.

Monodisperse magnetites anchored onto carbon nanotubes: a platform for cell imaging, magnetic manipulation and enhanced photothermal treatment of tumors

In this paper, a facile solvothermal synthesis method was developed to prepare monodisperse magnetites anchored onto multi-walled carbon nanotubes (MWNTs). The pristine MWNTs were treated with a mixture of concentrated sulfuric and nitric acids. The oxidized MWNTs (o-MWNTs) had abundant carboxylic groups on the surface, which have a strong ability to chelate metal ions like Fe³⁺. The obtained MWNTs-Fe₃O₄ nanomaterials allowed π-π stacking of fluorescein isothiocyanate (FITC) to monitor inside living cancer cells by fluorescence imaging. Cells labeled with MWNTs-Fe₃O₄ nanomaterials could be efficiently manipulated by a magnetic field due to the large magnetic moment of the iron oxide domain in the nanocomposites. The MWNTs-Fe₃O₄ nanomaterials have been demonstrated to be effective for in vivo photothermal treatment of tumors using mice implanted with human U87 tumors as a model.