Data on vibrational spectra of the langasites LnCrGeBeO (Ln = La, Pr, Nd) and calculations.

In "Lattice dynamics and structure of the new langasites LnCrGeBeO (Ln = La, Pr, Nd): vibrational spectra and calculations" [1], experimental and calculated results on lattice dynamics of the recently discovered new compounds LaCrGeBeO, PrCrGeBeO, and NdCrGeBeO are reported. These compounds belong to the langasite series and constitute a new class of low-dimensional antiferromagnets. The data presented in this article includes IR diffuse transmission spectra of powder samples of LnCrGeBeO (Ln = La, Pr, Nd) registered at room temperature with a Bruker 125HR Fourier spectrometer, Raman spectra taken in the backscattering geometry (also at room temperature) with a triple monochromator using the line 514, 5 nm of an argon laser as an excitation, results of the DFT calculations with the B3LYP and PBE0 hybrid functionals on the optimized crystal structures, eigenfrequencies and eigenvectors of the normal vibrational modes.

X-ray natural circular dichroism in langasite crystal.

Optical activity in the X-ray range stems from the electric-dipole-electric-quadrupole interference terms mixing multipoles of opposite parity, and can be observed exclusively in systems with broken inversion symmetry. The gyration tensor formalism is used to describe the X-ray optical activity in langasite LaGaSiO crystal with the P321 space group. An experimental study of the X-ray natural circular dichroism (XNCD) near the Ga K-edge in LaGaSiO single crystal was performed at ESRF beamline ID12, both along and perpendicular to the crystal optical axis.

Pressure-induced phase transitions of piezoelectric single crystals from the langasite family: La3Nb0.5Ga5.5O14 and La3Ta0.5Ga5.5O14.

The hydrostatic compression of piezoelectric single crystals of La(3)Nb(0.5)Ga(5.5)O(14) (LNG) and La(3)Ta(0.