Generation of clusterized structure of La$_{0.7}$Sr$_{0.3}$MnO$_{3-x}$ films in magnetron plasma: effect of electric fields and ion sound on particle levitation and “frozen” oscillations of film parameters

The influence of clusters of different sizes ($D$ = 50–400 $\mathring{\mathrm{A}}$) formed in magnetron plasma on the structure and properties of 36 samples of La$_{0.7}$Sr$_{0.3}$MnO$_{3-x}$ films deposited on glass along the particle flow was studied. As a result of comparing the “frozen” oscillations of film parameters with real ion-acoustic oscillations in the plasma, the scenario of its clusterization, which is impossible without particle levitation, was reconstructed. A phenomenological description of this phenomenon is proposed. It is shown that at distances from the target $L\le$ 2.15 cm, flow clustering is limited by the levitation of atomic clusters as a result of the balance between gravity, ion sound pressure and the force of interaction of charged particles with electric fields; the contribution of ion sound to particle levitation here does not exceed 12%. In the absence of an electric field ($L\ge$ 2.45 cm), levitation depends only on the entrainment of particles by ion-sound oscillations.