Unraveling the magnetic softness in Fe–Ni–B-based nanocrystalline material by magnetic small-angle neutron scattering

in IUCrJ (2022), 9(1), 65-72

Patterning enhanced tetragonality in BiFeO3 thin films with effective negative pressure by helium implantation

in Physical Review Materials (2021), 5(2), 024404

Helium implantation in epitaxial thin films is a way to control the out-of-plane deformation independently from the in-plane strain controlled by epitaxy. In particular, implantation by means of a helium ... [more ▼]

Helium implantation in epitaxial thin films is a way to control the out-of-plane deformation independently from the in-plane strain controlled by epitaxy. In particular, implantation by means of a helium microscope allows for local implantation and patterning down to the nanometer resolution, which is of interest for device applications. We present here a study of bismuth ferrite (BiFeO3) films where strain was patterned locally by helium implantation. Our combined Raman, x-ray diffraction, and transmission electron microscopy (TEM) study shows that the implantation causes an elongation of the BiFeO3 unit cell and ultimately a transition towards the so-called supertetragonal polymorph via states with mixed phases. In addition, TEM reveals the onset of amorphization at a threshold dose that does not seem to impede the overall increase in tetragonality. The phase transition from the R-like to T-like BiFeO3 appears as first-order in character, with regions of phase coexistence and abrupt changes in lattice parameters. [less ▲]

Thin-film (Sb,Bi)2Se3 Semiconducting Layers with Tunable Band Gaps Below 1 eV for Photovoltaic Applications

in Physical Review Applied (2020), 14

Microstructural-defect-induced Dzyaloshinskii-Moriya interaction

in Physical Review. B, Condensed Matter (2019), 99

Crossover in the pressure evolution of elementary distortions in RFeO3 perovskites and its impact on their phase transition

in Physical Review. B (2019), 99

This work reports on the pressure dependence of the octahedral tilts and mean Fe-O bond lengths in RFeO3 (R = Nd, Sm, Eu, Gd, Tb, and Dy), determined through synchrotron x-ray diffraction and Raman ... [more ▼]

This work reports on the pressure dependence of the octahedral tilts and mean Fe-O bond lengths in RFeO3 (R = Nd, Sm, Eu, Gd, Tb, and Dy), determined through synchrotron x-ray diffraction and Raman scattering, and their role on the pressure-induced phase transition displayed by all of these compounds. For larger rare-earth cations (Nd-Sm), both anti- and in-phase octahedral tilting decrease as pressure increases, whereas the reverse behavior is observed for smaller ones (Gd-Dy). EuFeO3 stands at the borderline, with nearly pressure-independent tilt angles. For the compounds where the tilts increase with pressure, the FeO6 octahedra are compressed at lower rates than for those ones exhibiting opposite pressure tilt dependence. The crossover between the two opposite pressure behaviors is discussed in relation to the general rules proposed from different theoretical approaches. The similarity of the pressure-induced isostructural insulator-to-metal phase transition, observed in the whole series, points out that the tilts play a minor role in its driving mechanisms. A clear relationship between octahedral compressibility and critical pressure is ascertained. [less ▲]

Effect of annealing conditions on the microstructure and magnetic properties of sintered Nd-Fe-B magnets as seen by magnetic small-angle neutron scattering

Scientific Conference (2018, August 29)

Combining X‐Ray Whole Powder Pattern Modeling, Rietveld and Pair Distribution Function Analyses as a Novel Bulk Approach to Study Interfaces in Heteronanostructures: Oxidation Front in FeO/Fe3O4 Core/Shell Nanoparticles as a Case Study

in Small: Nano Micro (2018)

Effect of annealing conditions on the microstructure and magnetic properties of sintered Nd-Fe-B magnets as seen by magnetic smallangle neutron scattering

in Materials Research Express (2018), 5

Resolving Inclusion Structure and Deformation Mechanisms in Polylactide Plasticized by Reactive Extrusion

in Macromolecular Materials and Engineering (2017)

Ag2Cu3Cr2O8(OH)4: a new bidimensional silver–copper mixed-oxyhydroxide with in-plane ferromagnetic coupling

in Dalton Transactions (2017), 46