Dual Crystal-Liquid Thermal Transport Behavior in MAPbCl.

Phonon dynamics in organic-inorganic hybrid perovskites (OIHPs) exhibit inherent complexity driven by the intricate interactions between rotatable organic cations and dynamically disordered inorganic octahedra, mediated by hydrogen bonding. This study aims to address this complexity by investigating the thermal transport behavior of MAPbCl as a gateway to the OIHPs family. The results reveal that the ultralow thermal conductivity of MAPbCl arises from a synergistic interplay of exceptionally low phonon velocities, short phonon lifetimes, and phonon mean free paths approaching the Regel-Ioffe limit.

First-principles study of the crystal and magnetic structures of multiferroic CuOCl.

Recently, the discovery of multiferroicity in pyrochlore-like compound CuOClhas generated significant interest, and several studies have been performed in this area. This transition metal oxychloride is unique because the divalent copper atoms create anS=1/2correlated insulator and the pyrochlore lattice tends to frustrate spins. From neutron powder diffraction measurements, an incommensurate magnetic order of the ordering vectorq=(0.

Higher superconducting transition temperature by breaking the universal pressure relation.

By investigating the bulk superconducting state via dc magnetization measurements, we have discovered a common resurgence of the superconducting transition temperatures (Ts) of the monolayer BiSrCuO (Bi2201) and bilayer BiSrCaCuO (Bi2212) to beyond the maximum Ts (Ts) predicted by the universal relation between T and doping () or pressure (P) at higher pressures. The T of underdoped Bi2201 initially increases from 9.6 K at ambient to a peak at 23 K at 26 GPa and then drops as expected from the universal T-P relation.

Magnetic ordering and dielectric relaxation in the double perovskite YBaCuFeO.

Using magnetization, dielectric constant, and neutron diffraction measurements on a high quality single crystal of YBaCuFeO (YBCFO), we demonstrate that the crystal shows two antiferromagnetic transitions at [Formula: see text] K and [Formula: see text] K, and displays a giant dielectric constant with a characteristic of the dielectric relaxation at T . It does not show the evidence of the electric polarization for the crystal used for this study. The transition at T corresponds with a paramagnetic to antiferromagnetic transition with a magnetic propagation vector doubling the unit cell along three crystallographic axes.