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A phenomenology-based model predictive controller (MPC) to control the electron density as desired set-point in Ar/SF6 capacitively coupled etch plasma was developed. The control model was established based on the power balance model and the dynamic characteristics of the equipment. The performance of the controller is evaluated through set-point tracking test, and it reveals that the MPC showed better performance compared to proportional integral derivative (PID) controller. It is expected that this MPC algorithm will be an element technology of an automated process controller to sustain the process plasma in the desired condition.

Ferromagnetic τ-phase Mn54Al46C2.44particles were synthesized, and its composites with commercial Sm2Fe17N3and synthesized Fe65Co35powders were fabricated. Smaller grain size than the single domain size of the Mn54Al46C2.44without obvious grain boundaries and secondary phases is the origin for the low intrinsic coercivity. It was confirmed that the magnetic properties of the Mn54Al46C2.44can be enhanced by magnetic exchange coupling with the hard magnetic Sm2Fe17N3and soft magnetic Fe65Co35. The high degrees of the exchange coupling were verified by calculating first derivative curves. Thermo-magnetic stabilities of the composites from 100 to 400 K were measured and compared. It was demonstrated that the Mn54Al46C2.44based composites containing Sm2Fe17N3and Fe65Co35could be promising candidates for future permanent magnetic materials with the proper control of purity, magnetic properties, etc.