相关论文: Superdislocations and point defects in pyrochlore …
The perovskite-like ferroelectric system PbZr(1-x)Ti(x)O3 (PZT) has a nearly vertical morphotropic phase boundary (MPB) around x=0.45-0.50. Recent synchrotron x-ray powder diffraction measurements by Noheda et al. [Appl. Phys. Lett. 74,…
We address a three-dimensional, coarse-grained description of dislocation networks at grain boundaries between rotated crystals. The so-called amplitude expansion of the phase-field crystal model is exploited with the aid of finite element…
We investigated the nature of the spin glass-like phase transition in the geometrically frustrated pyrochlore lattices Y$_{2}$Mo$_{2}$O$_{7}$ using the local probes nuclear and muon magnetic resonances, and the field-dependent long range…
Highly frustrated antiferromagnets composed of magnetic rare-earth moments are currently attracting much experimental and theoretical interest. Rare-earth ions generally have small exchange interactions and large magnetic moments. This…
Generally, lattice distortions play a key role in determining the ground states of materials. Although it is well known that trigonal distortions are generic to most two-dimensional transition metal dichalcogenides, the impact of this…
Sm$_2$Ti$_2$O$_7$, a member of rare-earth titanate pyrochlores, exhibits dipolar-octupolar antiferromagnetism below $T_N$ = 0.35 K. We observed two ferroelectric transitions at 182 ($T_{FE1}$) and 52 K ($T_{FE2}$), significantly higher than…
The spin ice system Dy$_{2}$Ti$_{2}$O$_{7}$ exhibits strong frequency-dependent spin-freezing at $\sim$ 16 K temperature. Although it has been a matter of discussion for years, the origin of this unusual spin freezing is still unknown. The…
We report structural and magnetic properties studies of large high quality single-crystals of the frustrated magnet, Nd$_2$Zr$_2$O$_7$. Powder x-ray diffraction analysis confirms that Nd$_2$Zr$_2$O$_7$ adopts the pyrochlore structure.…
Two-dimensional (2D) Janus Transition Metal Dichalcogenides (TMDs) have attracted much interest due to their exciting quantum properties arising from their unique two-faced structure, broken-mirror symmetry, and consequent colossal…
The local structural distortions in polydomain ferroelectric PbTiO3/SrTiO3 superlattices are investigated by means of high spatial and energy resolution electron energy loss spectroscopy combined with high angle annular dark field imaging.…
We report the growth of YFe2O4-\delta\ single crystals by the optical floating zone method, showing for the first time the same magnetization as highly stoichiometric (\delta = 0.00) powder samples and sharp superstructure reflections in…
While it is commonly accepted that the disorder induced by magnetic ion doping in quantum magnets usually generates a rugged free-energy landscape resulting in slow or glassy spin dynamics, the disorder/distortion effects associated with…
The properties of ferroelectric materials, such as lead zirconate titanate (PZT), are heavily influenced by the interaction of defects with domain walls. These defects are either intrinsic, or are induced by the addition of dopants. We…
We document the coexistence of ferro- and anti-ferromagnetism in pyrochlore $\rm Yb_2Ti_2O_7$ using three neutron scattering techniques on stoichiometric crystals: elastic neutron scattering shows a canted ferromagnetic ground state,…
Deformation band patterning in single crystals is investigated using a finite strain crystal viscoplasticity model based on the evolution of dislocation densities. In the presence of strong latent hardening and weak rate dependence, the…
Using transmission electron microscopy (TEM) we studied CaCu3Ti4O12, an intriguing material that exhibits a huge dielectric response, up to kilohertz frequencies, over a wide range of temperature. Neither in single crystals, nor in…
The Mott-insulating rare-earth titanates (RTiO$_3$, R being a rare-earth ion) are an important class of materials that encompasses interesting spin-orbital phases as well as ferromagnet-antiferromagnet and insulator-metal transitions. The…
A "supercooled" liquid develops when a fluid does not crystallize upon cooling below its ordering temperature. Instead, the microscopic relaxation times diverge so rapidly that, upon further cooling, equilibration eventually becomes…
We present an aberration corrected scanning transmission electron microscopy (ac-STEM) analysis of the perovskite (LaFeO3) and pyrochlore (Yb2Ti2O7 and Pr2Zr2O7) oxides and demonstrate that both the shape and contrast of visible atomic…
Dislocations in perovskite oxides have drawn increasing research interest due to their potential of tuning functional properties of electroceramics. Open questions remain regarding the behavior of dislocations concerning their stability…