Magnetic and structural properties of BiFeO{sub 3} thin films grown epitaxially on SrTiO{sub 3}/Si substrates

Journal Article · Tue May 07 00:00:00 EDT 2013 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4796150· OSTI ID:22102404

Laughlin, Ryan P.; Currie, Daniel A.; Contreras-Guererro, Rocio; Dedigama, Aruna; Priyantha, Weerasinghe; Droopad, Ravindranath; Theodoropoulou, Nikoleta ^[1]; Peng, Gao; Xiaoqing, Pan ^[2]

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1. Department of Physics, Texas State University-San Marcos, 601 University Drive, San Marcos, Texas 78666 (United States)
2. Material Science and Engineering, University of Michigan, 2105 H. H. Dow Bldg, 2300 Hayward Street, Ann Arbor, Michigan 48109 (United States)

The integration of oxides with semiconductors is important for the technological advancement of the next generation electronics. Concomitant ferroelectric and antiferromagnetic (AF) behavior is demonstrated in single crystal BiFeO{sub 3} (BFO) films grown on 20 nm SrTiO{sub 3} (STO) virtual substrates on Si(100) using molecular beam epitaxy (MBE). STO thin films are grown in an oxide MBE chamber by co-deposition of Sr, Ti, and molecular O{sub 2}. Careful control of the O{sub 2} during nucleation produced commensurate growth of STO on Si. The sequence of the steps allows for the suppression of an amorphous SiO{sub 2} layer. This STO(20 nm)/Si structure was used as a virtual substrate for MBE deposition of BFO on Si without breaking vacuum. BFO was deposited using Fe and O{sub 2} plasma with an overpressure of Bi flux, the growth rate was controlled by the incoming Fe flux. The reflection high energy electron diffraction image shows a 2-D growth front with a 6-fold surface reconstruction under optimized O{sub 2} pressure of 5 Multiplication-Sign 10{sup -8} mbar. Cross-sectional transmission electron microscopy (TEM) confirms the high crystallinity of the films and shows sharp, atomically flat interfaces. The selected area diffraction pattern (SADP) reveals that BFO grows in a distorted rhombohedral crystal structure. X-ray diffraction does not show formation of second phases and is consistent with the TEM and SADP results. The BFO films show AF behavior with a Neel temperature that exceeds 350 K, as expected (T{sub N} = 673 K) and with a residual ferromagnetic behavior that decreases with film thickness and is consistent with the G-type AF due to the canted spins. The saturation magnetization per unit volume for a 40 nm thick film was 180 emu/cm{sup 3} at an in-plane magnetic field of 8 kOe. The ferroelectric behavior of the films was verified using piezoresponse force microscopy.

• OSTI ID: 22102404
• Journal Information: Journal of Applied Physics, Vol. 113, Issue 17; Conference: 55. annual conference on magnetism and magnetic materials, Atlanta, GA (United States), 14-18 Nov 2010; Other Information: (c) 2013 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANTIFERROMAGNETIC MATERIALS
ANTIFERROMAGNETISM
BISMUTH COMPOUNDS
CRYSTAL STRUCTURE
ELECTRON DIFFRACTION
FERRITES
FERROELECTRIC MATERIALS
FERROMAGNETIC MATERIALS
MAGNETIC PROPERTIES
MAGNETIC SEMICONDUCTORS
MAGNETIZATION
MOLECULAR BEAM EPITAXY
NEEL TEMPERATURE
PIEZOELECTRICITY
STRONTIUM TITANATES
SUBSTRATES
THIN FILMS
TRANSMISSION ELECTRON MICROSCOPY
TRIGONAL LATTICES
X-RAY DIFFRACTION