Design of high-coercivity epitaxial magnetic garnet films for thermomagnetic recording and nanotechnology

•The nature of high-coercivity state in thin films of magnetic garnets.•The review of the methods of high-coercivity state design in magnetic garnet films.•Possibility of high coercivity inducing by creating electret state in magnetic films.

Tuning the magnetic hysteresis and optical absorption in single crystal epitaxial magnetic garnet films is investigated. It is demonstrated that high values of coercivity and optical absorption are caused by lattice mismatch stress and/or oxygen vacancies which compensate calcium anions in Ca-containing garnet films. Several methods for enhancing coercivity in Bi-containing films are studied: by doping bivalent impurity anions, by mismatch stress and by treatment in negative corona discharge. Optimization and comparative analysis of these methods are carried out discussing their pros and cons.