The microscopic dynamics of several phases of solid ethanol are studied under the same thermodynamic conditions by inelastic neutron scattering. It is found that the vibrational density of states of the orientational glass phase, where the molecules are arranged on an ordered lattice but with disordered orientations, is very similar to that of the structural glass phase, where the molecules are disordered both in position and orientation. Low-temperature specific heat measurements on the same phases strongly support the neutron measurements. We therefore find that positional disorder, even in a stoichiometrically homogeneous system such as ethanol, is not essential for the manifestation of glasslike behavior to an extent comparable with that exhibited by the structural glass.

A study of “inverted” core-shell, $\mathrm{MnO}/\gamma \mathrm{\text{−}}{\mathrm{Mn}}_2{\mathrm{O}}_3$, nanoparticles is presented. Crystal and magnetic structures and characteristic sizes have been determined by neutron diffraction for the antiferromagnetic core (MnO) and the ferrimagnetic shell ($\gamma \mathrm{\text{−}}{\mathrm{Mn}}_2{\mathrm{O}}_3$). Remarkably, while the MnO core is found to have a $T_N$ not far from its bulk value, the magnetic order of the $\gamma \mathrm{\text{−}}{\mathrm{Mn}}_2{\mathrm{O}}_3$ shell is stable far above $T_C$, exhibiting two characteristic temperatures, at $T\sim 40\mathrm{K}$ [$T_C(\gamma \mathrm{\text{−}}{\mathrm{Mn}}_2{\mathrm{O}}_3)$] and at $T\sim 120\mathrm{K}$ [$\sim T_N(\mathrm{MnO})$]. Magnetization measurements are consistent with these results. The stabilization of the shell moment up to $T_N$ of the core can be tentatively attributed to core-shell exchange interactions, hinting at a possible magnetic proximity effect.