In last decade years, we have payed attention to new bubble materials: monocrystalline epilayers and monocrystalline platelets of ferrites with spinel structure. In these materials cylindrical magnetic domains have been obtained. The perpendicular magnetic anisotropy occuring therein is a primary parameter, defining the properties of these bubble materials. The source of this anisotropy does not reside in the crystallographical structure of the materials, which are ferrimagnetics with cubic structure. The epilayers were obtained by CVD method on monocrystalline MgO substrates on the /100/ crystallographical surface in the 1100–1340 C temperature range. The dominant source of the perpendicular anisotropy observed in epilayer formed by CVD onto nonmagnetic substrates is magnetostriction. Can be summarized as follows: 1/ epilayers of ferrites are normally in a state of mechanical stress &sgr; due to mismatch between lattice constants. 2/ if the ferrite epilayer is magnetostrictive this stress produces a uniaxial magnetic anisotropy, 3/ with negative magnetostriction constants the easy axis is normal to the epilayer plane if this epilayer is in tension &sgr;≳0. The parameters characterizing the ferrite epilayers are: thickness 5 to 20 &mgr;m; 4&pgr;M=0.4 to 2 kGs; K1=104to 105ergs/cc; Kn=104to 105ergs/cc; collapse field Hcol=0.4 to 2 kOe; characteristic length 0.04 to 0.05 &mgr;m; bubble diameter 1 to 7 &mgr;m; bubble mobility, measured by FMR, is 40 to 250 cm/Oes and quality factorqabout 1.