Significant applications of SrTiO3 single crystals in electronics require knowledge about the influence structural imperfections on their optical properties. Birefringence temperature changes were investigated a few broad range, from 85 K to 250 K. The birefringence was found be non-linear function below transition Ts at 105 K, and indicatrix orientation accompanied it. A weak residual permanen...

The notion of a generalized helix in R3, a curve making a constant angle with a fixed direction, can be generalized to higher dimensions in many ways. In [7] the same definition is proposed but in R. In [4] the definition is more restrictive: the fixed direction makes a constant angle with all the vectors of the Frenet frame. It is easy to check that this definition only works in the odd dimens...

A mathematical approach has been developed to determine the optical orientation of biaxial minerals by combining spindle stage and X-ray-diffractometer measurements. First, a goniometer head, with crystal affixed, is screwed onto a spindle stage, and its orientation matrix for the biaxial indicatrix is determined. Next, the same goniometer head is transferred to a single-crystal Xray diffractom...

The phase diagram of (Tb,, Dyl-,) V04 was studied by crystal optical methods. The low-temperature properties of the mixed crystals are found to depend on the different distorted structures of the pure substances. In (Tb0.4, Dyo.6) VOr, two phase transitions are observed, resulting in a superposition of the two distortion types. DyV04 and TbV04 are well-known examples of a structural phase trans...

Let Mt be an isoparametric foliation on the unit sphere (Sn−1(1), gst) with d principal curvatures. Using spherical coordinates induced by Mt, we construct a Minkowski norm representation $$F = r\sqrt {2f(t)} $$ , which generalizes notions of (α, β)-norm and (α1, α2)-norm. technique local frame, give exact explicit answer to question when really defines norm. similar technique, study Hessian is...