Enhanced exchange bias in fully epitaxial Fe3O4/tetragonal-like BiFeO3 magnetoelectric bilayers
1 Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Institute of Advanced Materials Physics, Faculty of Science, Tianjin University Tianjin 300072, PRC
Received: 16 August 2013
Accepted: 3 January 2014
Fully epitaxial Fe3O4/BiFeO3 bilayers were deposited on (001) LaAlO3 and SrTiO3 by magnetron sputtering. BiFeO3 remained tetragonal on highly misfit-strain LaAlO3 substrates. Obvious exchange bias with a reciprocal relation to the thickness of ferromagnetic Fe3O4 was observed in the Fe3O4/tetragonal-like BiFeO3 (Fe3O4/T-BiFeO3) bilayers below which is similar to that of Fe3O4/rhombohedral-like BiFeO3 (Fe3O4/R-BiFeO3) bilayers. An unexpected enhancement of exchange bias from in Fe3O4/R-BiFeO3 to in the Fe3O4/T-BiFeO3 bilayer was observed at 3 K, which could be attributed to the enhanced Fe–O–Fe interfacial superexchange (SE) interaction induced by distorted T-BiFeO3.
PACS: 75.30.Et – Exchange and superexchange interactions / 75.85.+t – Magnetoelectric effects, multiferroics / 81.15.Cd – Deposition by sputtering
© EPLA, 2014