General One-Step Self-Assembly of Isostructural Intermetallic Co^II₃Ln^III Cubane Aggregates

A new family of Co/rare-earth intermetallic cubane aggregates [Co₃Ln­(hmp)₄(OAc)₅H₂O] (Ln = Dy, Ho, Er, Tm, Yb, Y) have been synthesized by self-assembly. Single-crystal X-ray diffraction analysis revealed that they are remarkably isostructural in showing a common [Co₃Ln] core. Magnetic studies showed that the Dy, Er, Tm, Yb, and Y complexes are ferromagnetic. The Dy complex exhibits the largest magnetocaloric effect (−Δ<i>S</i>_m = 12.58 J kg^–1 K^–1), which can be attributed to the large magnetic density of Dy^III

General One-Step Self-Assembly of Isostructural Intermetallic Co^II₃Ln^III Cubane Aggregates

A new family of Co/rare-earth intermetallic cubane aggregates [Co₃Ln­(hmp)₄(OAc)₅H₂O] (Ln = Dy, Ho, Er, Tm, Yb, Y) have been synthesized by self-assembly. Single-crystal X-ray diffraction analysis revealed that they are remarkably isostructural in showing a common [Co₃Ln] core. Magnetic studies showed that the Dy, Er, Tm, Yb, and Y complexes are ferromagnetic. The Dy complex exhibits the largest magnetocaloric effect (−Δ<i>S</i>_m = 12.58 J kg^–1 K^–1), which can be attributed to the large magnetic density of Dy^III

Sandwich-structured Fe2O3@SiO2@Au nanoparticles with magnetoplasmonic responses

We report a method for the fabrication of relatively uniform sandwich-like core-interlayer-shell nanostructures by using g-Fe2O3 as the inner core, SiO2 as the interlayer, and relatively uniform gold (Au) as the outer shell. The resulting novel hybrid nanoparticle combines the intense local fields of nanorods with the highly tunable plasmon resonances of nanoshells. The length and diameter of the resulting nanoparticles can be tuned by the aspect ratio of a-Fe2O3, the interlayer of SiO2 and the outer layer of Au. After calcination under H2 and then exposure to air, a-Fe2O3 was transformed into g-Fe2O3, which provides the hybrid particle magnetic tunability. This metal oxide (g-Fe2O3) dielectric core, the SiO2 interlayer and the Au shell spindle nanoparticle resemble a grain of Au nanorice (g-Fe2O3@SiO2@Au ellipsoids)...

A facile approach for screening isolated nanomagnetic behavior for bit-patterned media

10.1088/0957-4484/25/22/225203Nanotechnology2522-NNOT

Large Area Directed Self-Assembly of Sub-10 nm Particles with Single Particle Positioning Resolution

Directed self-assembly of nanoparticles (DSA-n) holds great potential for device miniaturization in providing patterning resolution and throughput that exceed existing lithographic capabilities. Although nanoparticles excel at assembling into regular close-packed arrays, actual devices on the other hand are often laid out in sparse and complex configurations. Hence, the deterministic positioning of single or few particles at specific positions with low defect density is imperative. Here, we report an approach of DSA-n that satisfies these requirements with less than 1% defect density over micrometer-scale areas and at technologically relevant sub-10 nm dimensions. This technique involves a simple and robust process where a solvent film containing sub-10 nm gold nanoparticles climbs against gravity to coat a prepatterned template. Particles are placed individually into nanoscale cavities, or between nanoposts arranged in varying degrees of geometric complexity. Brownian dynamics simulations suggest a mechanism in which the particles are pushed into the template by a nanomeniscus at the drying front. This process enables particle-based self-assembly to access the sub-10 nm dimension, and for device fabrication to benefit from the wealth of chemically synthesized nanoparticles with unique material properties

Large Area Directed Self-Assembly of Sub-10 nm Particles with Single Particle Positioning Resolution

Directed self-assembly of nanoparticles (DSA-n) holds great potential for device miniaturization in providing patterning resolution and throughput that exceed existing lithographic capabilities. Although nanoparticles excel at assembling into regular close-packed arrays, actual devices on the other hand are often laid out in sparse and complex configurations. Hence, the deterministic positioning of single or few particles at specific positions with low defect density is imperative. Here, we report an approach of DSA-n that satisfies these requirements with less than 1% defect density over micrometer-scale areas and at technologically relevant sub-10 nm dimensions. This technique involves a simple and robust process where a solvent film containing sub-10 nm gold nanoparticles climbs against gravity to coat a prepatterned template. Particles are placed individually into nanoscale cavities, or between nanoposts arranged in varying degrees of geometric complexity. Brownian dynamics simulations suggest a mechanism in which the particles are pushed into the template by a nanomeniscus at the drying front. This process enables particle-based self-assembly to access the sub-10 nm dimension, and for device fabrication to benefit from the wealth of chemically synthesized nanoparticles with unique material properties