Confined Chemical Fluid Deposition of Ferromagnetic Metalattices
| Autor: | Todd D. Day, Parivash Moradifar, Rongrui He, Yunzhi Liu, John V. Badding, Jennifer L. Russell, Nitin Samarth, Thomas E. Mallouk, Pengtao Xu, Shih Ying Yu, Vincent M. Torres, Nasim Alem, Suzanne E. Mohney, Susan Kempinger |
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| Rok vydání: | 2017 |
| Předmět: |
Materials science
Condensed matter physics Mechanical Engineering Degrees of freedom (physics and chemistry) Physics::Optics Bioengineering 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences 0104 chemical sciences Hysteresis Ferromagnetism Deposition (phase transition) General Materials Science SPHERES Thin film 0210 nano-technology Nanoscopic scale Quantum |
| Zdroj: | Nano Letters. 18:546-552 |
| ISSN: | 1530-6992 1530-6984 |
| DOI: | 10.1021/acs.nanolett.7b04633 |
| Popis: | A magnetic, metallic inverse opal fabricated by infiltration into a silica nanosphere template assembled from spheres with diameters less than 100 nm is an archetypal example of a "metalattice". In traditional quantum confined structures such as dots, wires, and thin films, the physical dynamics in the free dimensions is typically largely decoupled from the behavior in the confining directions. In a metalattice, the confined and extended degrees of freedom cannot be separated. Modeling predicts that magnetic metalattices should exhibit multiple topologically distinct magnetic phases separated by sharp transitions in their hysteresis curves as their spatial dimensions become comparable to and smaller than the magnetic exchange length, potentially enabling an interesting class of "spin-engineered" magnetic materials. The challenge to synthesizing magnetic inverse opal metalattices from templates assembled from sub-100 nm spheres is in infiltrating the nanoscale, tortuous voids between the nanospheres void-free with a suitable magnetic material. Chemical fluid deposition from supercritical carbon dioxide could be a viable approach to void-free infiltration of magnetic metals in view of the ability of supercritical fluids to penetrate small void spaces. However, we find that conventional chemical fluid deposition of the magnetic late transition metal nickel into sub-100 nm silica sphere templates in conventional macroscale reactors produces a film on top of the template that appears to largely block infiltration. Other deposition approaches also face difficulties in void-free infiltration into such small nanoscale templates or require conducting substrates that may interfere with properties measurements. Here we report that introduction of "spatial confinement" into the chemical fluid reactor allows for fabrication of nearly void-free nickel metalattices by infiltration into templates with sphere sizes from 14 to 100 nm. Magnetic measurements suggest that these nickel metalattices behave as interconnected systems rather than as isolated superparamagnetic systems coupled solely by dipolar interactions. |
| Databáze: | OpenAIRE |
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