Multiferroic and fatigue behavior of (Bi0.90 La0.10) FeO3 / CoFe2 O4 / (Bi0.90 La0.10) FeO3 sandwich structure

Abstract

Multiferroic (Bi0.90 La0.10) FeO3 / CoFe2 O 4 / (Bi0.90 La0.10) FeO3 (BLFO/CFO/BLFO) thin films were grown by radio-frequency sputtering on a SrRuO3 -buffered Pt/ TiO2 / SiO2 /Si substrate. To modulate their multiferroic behavior, the CFO layer thickness was varied, while the thickness of the BLFO layer was kept unchanged. Both ferroelectric and ferromagnetic behaviors of the BLFO/CFO/BLFO thin films were shown to depend on the thickness of the CFO layer. The BLFO/CFO (100 nm)/BLFO sand-wich structure demonstrated a giant polarization, a much improved ferromagnetic behavior (2 Pr =171.8 μC/ cm2, 2 Ec =768.0 kV/cm, Hc =701 Oe, and Ms =218 emu/ cm3), and enhanced fatigue endurance. While the underlying physical mechanisms were discussed, the BLFO/CFO/BLFO sandwich structure represents a promising lead-free multiferroic behavior. © 2009 The Electrochemical Society.