Growth and magneto-optical properties of Na0.37Tb0.63F2.26 cubic single crystal

Crystals of Na_0.37Tb_0.63F_2.26 solid solution with a fluorite structure have been grown from melt by the Bridgman technique. The measured values of the Verdet constant are V = 0.35 ± 0.02 and 0.105 ± 0.01 arcmin/(Oe cm) for λ = 633 and 1060 nm, respectively. The dispersion of the Verdet constant is studied in the range of 380–1060 nm. The Na_0.37Tb_0.63F_2.26 crystal is somewhat inferior to the previously studied noncubic fluoride crystals containing Tb³⁺ ions yields by V(λ) and is close to KTb₃F₁₀ crystal in totality of properties.     

Unique solvability of a non‐local problem for mixed‐type equation with fractional derivative

In this work, we investigate a boundary problem with non‐local conditions for mixed parabolic–hyperbolic‐type equation with three lines of type changing with Caputo fractional derivative in the parabolic part. We equivalently reduce considered problem to the system of second kind Volterra integral equations. In the parabolic part, we use solution of the first boundary problem with appropriate Green's function, and in hyperbolic parts, we use corresponding solutions of the Cauchy problem. Copyright © 2016 John Wiley & Sons, Ltd.     

Growth of congruently melting Ca0.59Sr0.41F2 crystals and study of their properties

Homogeneous crystals of Ca_0.59Sr_0.41F₂ alloy (sp. gr., Fm $ \bar 3 $ \bar 3 m, a = 0.56057 nm), corresponding to the point of minimum in the melting curve in the CaF₂-SrF₂ phase diagram, have been grown by the vertical Bridgman method. The optical, mechanical, electrical, and thermophysical properties of Ca_0.59Sr_0.41F₂ and MF₂ crystals (M = Ca, Sr) have been studied and comparatively analyzed. Ca_0.59Sr_0.41F₂ crystals are transparent in the range of 0.133–11.5 μm, have refractive index n _D = 1.436, microhardness H _μ = 2.63 ± 0.10 GPa, ion conductivity σ = 5 × 10⁻⁵ S/cm at 825 K, and thermal conductivity k = 4.0 W m⁻¹ K⁻¹ at 300 K. It is shown that the optical properties of Ca_0.59Sr_0.41F₂ crystals are intermediate between those of CaF₂ and SrF₂, whereas their mechanical and electrical characteristics are better than the latter compounds.