Maradudin A.A., Simonsen I. «Rayleigh and Wood anomalies in the diffraction of acoustic waves from the periodically corrugated surface of an elastic medium» Физика низких температур, 42, № 5, с. 455-462 (2016)

By the use of the Rayleigh method we have calculated the angular dependence of the reflectivity and the efficiencies of several other diffracted orders when the periodically corrugated surface of an isotropic elastic medium is illuminated by a volume acoustic wave of shear horizontal polarization. These dependencies display the signatures of Rayleigh and Wood anomalies, usually associated with the diffraction of light from a metallic grating. The Rayleigh anomalies occur at angles of incidence at which a diffracted order appears or disappears; the Wood anomalies here are caused by the excitation of the shear horizontal surface acoustic waves supported by the periodically corrugated surface of an isotropic elastic medium. The dispersion curves of these waves in both the nonradiative and radiative regions of the frequency-wavenumber plane are calculated, and used in predicting the angles of incidence at which the Wood anomalies are expected to occur.

Felea V., Prodan L., Stefanet E., Cong P.T., Zherlitsyn S., Tsurkan V. «Ultrasound propagation in bond frustrated HgCr₂S₄ spinel in magnetic fields» Физика низких температур, 43, № 5, с. 702-706 (2017)

Ultrasound and magnetization studies of bond frustrated spinel HgCr₂S₄ are performed as a function of temperature in static magnetic fields. Beside the anharmonic effect, the sound velocity shows pronounced anomaly at the antiferromagnetic (AFM) transition at T_N=23 K with an additional significant increase of the order of 0.5% indicating a strong spin-lattice coupling. External magnetic fields enhance the ferromagnetic (FM) correlations and shift the anomalies to lower temperatures concomitantly with the reduction of the Neel temperature. The constructed H–T phase diagram beside the long-range AFM states reveals the state with induced FM order and regimes with short-range AFM and FM correlations as well.

Strazzulla G. «Crystalline and amorphous structure of astrophysical ices» Физика низких температур, 39, № 5, с. 556-559 (2013)

The structure of water and other ices strongly depends on the temperature at which they formed, e.g., by vapor deposition. It is amorphous if ices are formed at low temperature (e.g., 10–30 K for water ice), or crystalline if the deposition temperature is higher (140–150 K). Ices have a “polycrystalline” structure at intermediate temperatures. The crystalline structure of ices can be damaged up to a complete amorphization by processes such as those due to energetic ion bombardment. Here I describe some experimental results obtained by ion irradiation of water and ammonia ices, two species particularly relevant in astrophysics. The results are discussed in the light of the relevance they have in astronomical environments where the actual structure of the ices depends on a competition between energetic processing that induce amorphization and thermal annealing that favors the transition towards more ordered structures.