@article{21525,
  abstract     = {We present a novel design for an ultracompact, passive light source capable of generating ultraviolet and X-ray radiation, based on the interaction of free electrons with the magnetic near-field of a ferromagnet. Our design is motivated by recent advances in the fabrication of nanostructures, which allow the confinement of large magnetic fields at the surface of ferromagnetic nanogratings. Using ab initio simulations and a complementary analytical theory, we show that highly directional, tunable, monochromatic radiation at high frequencies could be produced from relatively low-energy electrons within a tabletop design. The output frequency is tunable in the extreme ultraviolet to hard X-ray range via electron kinetic energies from 1 keV to 5 MeV and nanograting periods from 1 μm to 5 nm. The proposed radiation source can achieve the tunability and monochromaticity of current free-electron-driven sources (free-electron lasers, synchrotrons, and laser-driven undulators), yet with a significantly reduced scale, cost, and complexity. Our design could help realize the next generation of tabletop or on-chip X-ray sources.},
  author       = {Fisher, Sophie and Roques-Carmes, Charles and Rivera, Nicholas and Wong, Liang Jie and Kaminer, Ido and Soljačić, Marin},
  issn         = {2330-4022},
  journal      = {ACS Photonics},
  keywords     = {X-ray sources, free electrons, nanostructure, undulator, synchrotron, free-electron laser},
  number       = {5},
  pages        = {1096--1103},
  publisher    = {American Chemical Society },
  title        = {{Monochromatic X-ray source based on scattering from a magnetic nanoundulator}},
  doi          = {10.1021/acsphotonics.0c00121},
  volume       = {7},
  year         = {2020},
}

@article{371,
  abstract     = {The design and engineering of earth-abundant catalysts that are both cost-effective and highly active for water splitting are crucial challenges in a number of energy conversion and storage technologies. In this direction, herein we report the synthesis of Fe3O4@NiFexOy core-shell nanoheterostructures and the characterization of their electrocatalytic performance toward the oxygen evolution reaction (OER). Such nanoparticles (NPs) were produced by a two-step synthesis procedure involving the colloidal synthesis of Fe3O4 nanocubes with a defective shell and the posterior diffusion of nickel cations within this defective shell. Fe3O4@NiFexOy NPs were subsequently spin-coated over ITO-covered glass and their electrocatalytic activity toward water oxidation in carbonate electrolyte was characterized. Fe3O4@NiFexOy catalysts reached current densities above 1 mA/cm2 with a 410 mV overpotential and Tafel slopes of 48 mV/dec, which is among the best electrocatalytic performances reported in carbonate electrolyte.},
  author       = {Luo, Zhishan and Márti Sánchez, Sara and Nafria, Raquel and Joshua, Gihan and De La Mata, Maria and Guardia, Pablo and Flox, Christina and Martínez Boubeta, Carlos and Simeonidis, Konstantinos and Llorca, Jordi and Morante, Joan and Arbiol, Jordi and Ibanez Sabate, Maria and Cabot, Andreu},
  issn         = {1944-8252},
  journal      = {Applied Materials and Interfaces},
  keywords     = {nanoparticle, iron oxide, magnetite, core−shell nanostructure, electrocatalysts, oxygen evolution reaction, OER},
  number       = {43},
  pages        = {29461 -- 29469},
  publisher    = {American Chemical Society},
  title        = {{Fe3O4@NiFexOy nanoparticles with enhanced electrocatalytic properties for oxygen evolution in carbonate electrolyte}},
  doi          = {10.1021/acsami.6b09888},
  volume       = {8},
  year         = {2016},
}