Origin of the large dispersion of magnetic properties in nanostructured oxides: FexO/Fe3O4 nanoparticles as a case study.
Nanoscale 7(7):3002 (2015)
The intimate relationship between stoichiometry and physicochemical properties in transition-metal oxides makes them appealing as tunable materials. These features become exacerbated when dealing with nanostructures. However, due to the complexity of nanoscale materials, establishing a distinct ...
Direct evidence for an interdiffused intermediate layer in bi-magnetic core-shell nanoparticles.
Nanoscale 6(20):11911 (2014)
Core-shell nanoparticles attract continuously growing interest due to their numerous applications, which are driven by the possibility of tuning their functionalities by adjusting structural and morphological parameters. However, despite the critical role interdiffused interfaces may have in the...
Oxide Wizard: an EELS application to characterize the white lines of transition metal edges.
Microscopy and Microanalysis 20(3):698 (2014)
Physicochemical properties of transition metal oxides are directly determined by the oxidation state of the metallic cations. To address the increasing need to accurately evaluate the oxidation states of transition metal oxide systems at the nanoscale, here we present "Oxide Wizard." This script...
Green electrochemical template synthesis of CoPt nanoparticles with tunable size, composition, and magnetism from microemulsions using an ionic liquid (bmimPF6).
ACS Nano 8(5):4630 (2014)
Electrodeposition from microemulsions using ionic liquids is revealed as a green method for synthesizing magnetic alloyed nanoparticles, avoiding the use of aggressive reducing agents. Microemulsions containing droplets of aqueous solution (electrolytic solution containing Pt(IV) and Co(II) ions...
Magnetic properties of single crystalline expanded austenite obtained by plasma nitriding of austenitic stainless steel single crystals.
ACS Applied Materials & Interfaces 5(20):10118 (2013)
Ferromagnetic single crystalline , , and -oriented expanded austenite is obtained by plasma nitriding of paramagnetic 316L austenitic stainless steel single crystals at either 300 or 400 °C. After nitriding at 400 °C, the  direction appears to constitute the magnetic easy axi...
Tuning the magneto-optical response of nanosize ferromagnetic Ni disks using the phase of localized plasmons.
Physical Review Letters 111(16):167401 (2013)
We explore the influence of the phase of localized plasmon resonances on the magneto-optical activity of nanoferromagnets. We demonstrate that these systems can be described as two orthogonal damped oscillators coupled by the spin-orbit interaction. We prove that only the spin-orbit induced tran...
Controlled 3D-coating of the pores of highly ordered mesoporous antiferromagnetic Co3O4 replicas with ferrimagnetic Fe(x)Co(3-x)O4 nanolayers.
Nanoscale 5(12):5561 (2013)
The controlled filling of the pores of highly ordered mesoporous antiferromagnetic Co3O4 replicas with ferrimagnetic FexCo3-xO4 nanolayers is presented as a proof-of-concept toward the integration of nanosized units in highly ordered, heterostructured 3D architectures. Antiferromagnetic (AFM) Co...
Improving the magnetic properties of Co-CoO systems by designed oxygen implantation profiles.
ACS Applied Materials & Interfaces 5(10):4320 (2013)
Oxygen implantation in ferromagnetic Co thin films is shown to be an advantageous route to improving the magnetic properties of Co-CoO systems by forming multiple nanoscaled ferromagnetic/antiferromagnetic interfaces homogeneously distributed throughout the layer. By properly designing the impla...
Polarizability and magnetoplasmonic properties of magnetic general nanoellipsoids.
Optics Express 21(8):9875 (2013)
An approach to compute the polarizability tensor of magnetic nanoparticles having general ellipsoidal shape is presented. We find a surprisingly excellent quantitative agreement between calculated and experimental magneto-optical spectra measured in the polar Kerr configuration from nickel nanod...
Resolving material-specific structures within Fe₃O₄|γ-Mn₂O₃ core|shell nanoparticles using anomalous small-angle X-ray scattering.
ACS Nano 7(2):921 (2013)
Here it is demonstrated that multiple-energy, anomalous small-angle X-ray scattering (ASAXS) provides significant enhancement in sensitivity to internal material boundaries of layered nanoparticles compared with the traditional modeling of a single scattering energy, even for cases in which high...
Designer magnetoplasmonics with nickel nanoferromagnets.
Nano Letters 11(12):5333 (2011)
We introduce a new perspective on magnetoplasmonics in nickel nanoferromagnets by exploiting the phase tunability of the optical polarizability due to localized surface plasmons and simultaneous magneto-optical activity. We demonstrate how the concerted action of nanoplasmonics and magnetization...
Two-, three-, and four-component magnetic multilayer onion nanoparticles based on iron oxides and manganese oxides.
Journal of the American Chemical Society 133(42):16738 (2011)
Magnetic multilayered, onion-like, heterostructured nanoparticles are interesting model systems for studying magnetic exchange coupling phenomena. In this work, we synthesized heterostructured magnetic nanoparticles composed of two, three, or four components using iron oxide seeds for the subseq...
Plasmonic nickel nanoantennas.
Small 7(16):2341 (2011)
The fundamental optical properties of pure nickel nanostructures are studied by far-field extinction spectroscopy and optical near-field microscopy, providing direct experimental evidence of the existence of particle plasmon resonances predicted by theory. Experimental and calculated near-field ...
Grain boundary segregation and interdiffusion effects in nickel-copper alloys: an effective means to improve the thermal stability of nanocrystalline nickel.
ACS Applied Materials & Interfaces 3(7):2265 (2011)
Nanocrystalline (nc) Ni films show pronounced grain growth and suffer from concomitant deterioration of their mechanical and magnetic properties after annealing at relatively low temperatures (T(ANN) ≥ 475 K). This constitutes a drawback for their applicability as coatings or in components of mi...
Out-of-plane magnetic patterning based on indentation-induced nanocrystallization of a metallic glass.
Small 6(14):1543 (2010)
Periodic arrays of micrometer-sized ferromagnetic structures with perpendicular magnetic anisotropy are prepared by nanoindentation at the surface of a Fe(67.7)B(20)Cr(12)Nb(0.3) glassy ribbon initially showing in-plane magnetic anisotropy. The indented regions exhibit enhanced coercivity and sa...
Size-dependent passivation shell and magnetic properties in antiferromagnetic/ferrimagnetic core/shell MnO nanoparticles.
Journal of the American Chemical Society 132(27):9398 (2010)
The magnetic properties of bimagnetic core/shell nanoparticles consisting of an antiferromagnetic MnO core and a ferrimagnetic passivation shell have been investigated. It is found that the phase of the passivation shell (gamma-Mn(2)O(3) or Mn(3)O(4)) depends on the size of the nanoparticles. St...
Direct magnetic patterning due to the generation of ferromagnetism by selective ion irradiation of paramagnetic FeAl alloys.
Small 5(2):229 (2009)
Sub-100-nm magnetic dots embedded in a non-magnetic matrix are controllably generated by selective ion irradiation of paramagnetic Fe(60)Al(40) (atomic %) alloys, taking advantage of the disorder-induced magnetism in this material. The process is demonstrated by sequential focused ion beam irrad...
Assessment of catalyst particle removal in multi-wall carbon nanotubes by highly sensitive magnetic measurements
Carbon 47(3):758 (2009)
The purity of the multi-wall carbon nanotubes (MWCNTs) from catalyst nanoparticles (cobalt and iron) after conventional nitric acid refluxing has been assessed by standard methods and magnetic measurements. X-ray diffraction and energy dispersive X-ray spectroscopy analyses are not suitable...
Steam purification for the removal of graphitic shells coating catalytic particles and the shortening of single-walled carbon nanotubes.
Small 4(9):1501 (2008)
Purification and shortening of single-walled carbon nanotubes (SWNTs) is carried out by treatment with steam. During the steam purification the graphitic shells coating the catalytic metal particles are removed. Consequently, the exposed catalytic particles can be easily dissolved by treatment w...
Synthesis and size-dependent exchange bias in inverted core-shell MnO|Mn3O4 nanoparticles.
Journal of the American Chemical Society 129(29):9102 (2007)
Core-shell nanoparticles of MnO|Mn3O4 with average particle sizes of 5-60 nm, composed of an antiferromagnetic (AFM) core and a ferrimagnetic (FiM) shell, have been synthesized and their magnetic properties investigated. The core-shell structure has been generated by the passivation of the MnO c...