Anomalous thickness-dependent strain states and strain-tunable magnetization in Zn-doped ferrite epitaxial films

Journal Article · Wed May 07 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4874920· OSTI ID:22273465

Yang, Y. J.; Bao, J.; Yang, M. M.; Hu, C. S.; Chen, X. C.; Pan, G. Q. ^[1]; Huang, H. L. ^[2]; Zhang, S.; Wang, J. W.; Li, P. S.; Liu, Y.; Zhao, Y. G. ^[3]; Jiang, T.; Liu, Y. K.; Li, X. G. ^[4]

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1. National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230026 (China)
2. CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China)
3. Department of Physics and State Key Laboratory of New Ceramics, Fine Processing, Tsinghua University, Beijing 100084 (China)
4. Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science, Technology of China, Hefei, Anhui 230026 (China)

A series of Zn{sub x}Fe{sub 3−x}O{sub 4} (ZFO, x = 0.4) thin films were epitaxially deposited on single-crystal (001)-SrTiO{sub 3} (STO) substrates by radio frequency magnetron sputtering. The anomalous thickness-dependent strain states of ZFO films were found, i.e., a tensile in-plane strain exists in the thinner ZFO film and which monotonously turns into compressive in the thicker films. Considering the lattice constant of bulk ZFO is bigger than that of STO, this strain state cannot be explained in the conventional framework of lattice-mismatch-induced strain in the hetero-epitaxial system. This unusual phenomenon is proposed to be closely related to the Volmer-Weber film growth mode in the thinner films and incorporation of the interstitial atoms into the island's boundaries during subsequent epitaxial growth of the thicker films. The ZFO/STO epitaxial film is found in the nature of magnetic semiconductor by transport measurements. The in-plane magnetization of the ZFO/STO films is found to increase as the in-plane compressive strain develops, which is further proved in the (001)-ZFO/PMN-PT film where the film strain state can be in situ controlled with applied electric field. This compressive-strain-enhanced magnetization can be attributed to the strain-mediated electric-field-induced in-plane magnetic anisotropy field enhancement. The above results indicate that strain engineering on magnetic oxide semiconductor ZFO films is promising for novel oxide-electronic devices.

• OSTI ID: 22273465
• Journal Information: Journal of Applied Physics, Vol. 115, Issue 17; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANISOTROPY
CRYSTAL DEFECTS
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
ELECTRIC FIELDS
EPITAXY
FERRITES
LATTICE PARAMETERS
MAGNETIC SEMICONDUCTORS
MAGNETIZATION
MONOCRYSTALS
RADIOWAVE RADIATION
SPUTTERING
STRAINS
STRONTIUM TITANATES
SUBSTRATES
THIN FILMS
ZINC COMPOUNDS