MULTIFERROIC BIFEO3-BASED THIN FILMS AND DEVICES: MANIPULATION OF CRYSTAL STRUCTURES AND PHYSICAL PROPERTIES

Abstract

MULTIFERROICS, WHICH EXHIBIT SIMULTANEOUSLY COUPLED TWO OR MORE FERROIC (FERROELECTRIC, FERROMAGNETIC, AND FERROELASTIC) ORDERS, HAVE ATTRACTED ENORMOUS RESEARCH INTEREST IN THE LAST DECADE. THE CELEBRATED RENAISSANCE OF MULTIFERROICS PROBABLY BEGAN WITH THE STUDY OF A PARADIGMATIC MEMBER ? BIFEO3 (BFO). A VAST NUMBER OF PREVIOUS INVESTIGATIONS INTO BFO HAVE REVEALED ITS VERSATILE CRYSTAL STRUCTURES AND A BROAD PALETTE OF PHYSICAL PROPERTIES. THE COEXISTENCE OF INTRIGUING STRUCTURAL, FERROELECTRIC, MAGNETIC AND OPTICAL PROPERTIES, AND THE CROSS-COUPLING BETWEEN THEM, ENDOW BFO A UNIQUE POTENTIAL FOR MULTIFUNCTIONAL DEVICES. IN THIS THESIS, SEVERAL APPROACHES INCLUDING STRAIN ENGINEERING, B-SITE SUBSTITUTION, AND IN COMBINATION WITH OTHER FUNCTIONAL SEMICONDUCTORS, HAVE BEEN STUDIED TO TUNE AND MANIPULATE THE CRYSTAL STRUCTURES AND PHYSICAL PROPERTIES OF BFO.