Multi-Segmented Nanowires: A High Tech Bright Future

In the last couple of decades, there has been a lot of progress in the synthesis methods of nano-structural materials, but still the field has a large number of puzzles to solve. Metal nanowires (NWs) and their alloys represent a sub category of the 1-D nano-materials and there is a large effort to study the microstructural, physical and chemical properties to use them for further industrial applications. Due to technical limitations of single component NWs, the hetero-structured materials gained attention recently. Among them, multi-segmented NWs are more diverse in applications, consisting of two or more segments that can perform multiple function at a time, which confer their unique properties. Recent advancement in characterization techniques has opened up new opportunities for understanding the physical properties of multi-segmented structures of 1-D nanomaterials. Since the multi-segmented NWs needs a reliable response from an external filed, numerous studies have been done on the synthesis of multi-segmented NWs to precisely control the physical properties of multi-segmented NWs. This paper highlights the electrochemical synthesis and physical properties of multi-segmented NWs, with a focus on the mechanical and magnetic properties by explaining the shape, microstructure, and composition of NWs.

Evidence of magneto-structural coupling affecting magnetic anisotropy in a cobalt nano-composite

By investigating temperature dependent structural and magnetic properties of cobalt (Co) embedded within nanoporous anodized alumina template, we observe changes in the easy axis of Co magnetization and an unusual increase in its saturation magnetization below a temperature T _cr. Analysis of our M(H) data reveals that the magnetized volume of the sample increases rapidly as T falls below T _cr. To understand these features we perform micro-magnetic simulations for a single Co-nanopillar wherein by varying its magneto-crystalline anisotropy energy we are able to show that the changes observed near T _cr are related to the changes in the magnetic anisotropy of the nanopillar. We propose crystallographic structural distortions trigger changes in the balance between shape and magneto-crystalline anisotropy in our nanopillar. Our results suggest interplay between magnetism, structure and magnetic anisotropy in low dimensional Co-nanopillars, which can be modified with temperature of the system.

Preparation of broccoli-like ferromagnetic cobalt microstructures with superior coercivity via an aqueous reduction strategy

Controlled synthesis of novel hierarchical cobalt (Co) microstructures with extraordinary magnetic performances is a promising strategy for the development of magnetic metals for industrial purposes.