Stephen J. Pennycook

TL;DR: Strong binding and mutual repulsion of La atoms effectively pin the surface and inhibit both sintering and the transformation to α-Al2O3, providing the first guidelines for the choice of dopants to prevent thermal degradation of catalysts and other porous materials.

TL;DR: In this article, the authors review the historical attempts to resolve two principal questions that have each been extensively debated, but in independent communities: (1) What is the distribution of vacancies over the two cation sublattices in the nominal spinel structure, and (2) what is the hydrogen content of γ-alumina, if any.

Abstract: Ferroelectric domain nucleation and growth in multiferroic BiFeO3 films is observed directly by applying a local electric field with a conductive tip inside a scanning transmission electron microscope. The nucleation and growth of a ferroelastic domain and its interaction with pre-existing 71° domain walls are observed and compared with the results of phase-field modeling. In particular, a preferential nucleation site and direction-dependent pinning of domain walls are observed due to slow kinetics of metastable switching in the sample without a bottom electrode. These in situ spatially resolved observations of a first-order bias-induced phase transition reveal the mesoscopic mechanisms underpinning functionality of a wide range of multiferroic materials.

TL;DR: In this paper, the authors reported unambiguous magnetic manipulation of valley Zeeman splitting at 300 K and 10 K in a CVD-grown Fe-doped MoS2 monolayer; the effective Lande geff factor can be tuned to -20.7 by increasing the Fe dopant concentration.

TL;DR: In this paper, the influence of biaxial tensile strain on the electronic and Li+ ion conductivities of LiFePO4 was explored by performing first-principles calculations.