Temperature study of elastic properties of scandium-substituted hexaferrites

The acoustic method has been applied to study the temperature behaviour of elastic constants of single crystals BaScxFe12-xO19 (x=1.25; 1.65) in the 80-360 K range and external magnetic fields to 20 kOe. it is shown that all elastic constants have anomalies. They are observed in the 135 and 220 K regions for the x-1.25 composition; for the x=1.65 some additional peculiarities at 260 K and 140 K are found except critical points at 220 K and 329 K known from literature. It is supposed that 260 K and 140 K points are connected with changes in the magnetic moment projection on the basis plane. The external magnetic field application does not change the temperature behaviour of elastic constants of these crystals except for the 200 K region for x=1.65 composition