Anisotropic magnetic nanoparticles: A review of their properties, syntheses and potential applications

Air‐Stable Carbon‐Fe Based Magnetic Nanostructures

“…In case of elongated nanoparticles, e.g., nanorods and nanowires, the effective anisotropy of the material is influenced by both magnetocrystalline anisotropy and shape anisotropy, but the latter dominates over the former , . The magnetic moments in nanorods and nanowires align in a direction or directions, which is referred to as the magnetic easy axis, and responds to a magnetic field . In particular, Dumestre et al experimentally showed that materials with shape anisotropy produce enhanced H C values in case of Co nanorods with various aspect ratios .…”

“…[56,57] The magnetic moments in nanorods and nanowires align in a direction or directions, which is referred to as the magnetic easy axis, and responds to a magnetic field. [58] In particular, Dumestre et al experimentally showed that materials with shape anisotropy produce enhanced H C values in case of Co nanorods with various aspect ratios. [59] In our case, samples of Fe 3 C nanorods, in particular, Fe-1c sample produced higher coercive field over the sample Fe-1(500) with spherical Fe 3 C nanoparticles, which could be ascribed to shape anisotropy.…”

Programmable Atom Equivalents: Atomic Crystallization as a Framework for Synthesizing Nanoparticle Superlattices

“…A separate strategy to control valency and directional binding in PAEs relies on isotropically functionalizing a nonspherical NP, such that the shaped core acts as scaffold whose local geometry enforces direction on the DNA binding groups . This method is particularly promising given the wide array of synthetic protocols able to produce anisotropic NPs . It was demonstrated that anisotropic NPs with flat faces tend to favor arrangements in which these flat faces are aligned parallel with one another in order to maximize DNA hybridization interactions, a concept understood as shape complementarity .…”

“…Extending this strategy of imposing boundary conditions on PAE crystallite growth, the Summertop formalism (where nucleation and growth are restricted by multiple interfaces) could also be investigated by assembling PAEs at surfaces with concave or convex shapes. Alternatively, just as metal NPs of varying shapes have been synthesized through the introduction of facet capping agents during nucleation and growth, it may be possible to manipulate PAE superlattice crystal shape using nanoscale “capping” constructs. Each of these hypotheses to control PAE crystal habit utilizes an atomic mechanism as inspiration.…”

“…In NP‐based materials, properties are garnered through the collective properties of the constituent composite materials (i.e., PAE core composition, Section . ), but, more importantly, emergent properties can arise from an ordered, nanoscale structure, which PAEs are able to provide with exquisite programmability (Section .). While many of the properties that will be discussed in this subsection have only been proposed and not yet realized, it is important to note that PAEs do indeed provide a unique platform for studying structure–property relationships.…”