Mixed layer – structured ferroelectrics on the basis of mbox{sffamilybfseries Bi}_{hbox{sffamilybfseriesfontsize{12}{12}selectfont 4}} mbox{sffamilybfseries Ti}_{hbox{sffamilybfseriesfontsize{12}{12}selectfont 3}} mbox{sffamilybfseries O}_{hbox{sffamilybfseriesfontsize{12}{12}selectfont 12}}

Thermal diffusivities of pure YVO₄ single crystal and single crystals doped with Nd, Tm and Ca ions are measured using a modified ?ngstr?m's method. Measurements were carried out for main crystallographic directions ([100], [010] and [001]). Obtained results show that the thermal diffusivity in [001] direction is considerably higher than in (001) plane. Decrease of the thermal diffusivity is observed with growing concentration of dopants. For the heavier doped sample (5% at. of Tm + 0.4% at. of Ca) a drop of the thermal diffusivity is about 35%.