Ferrimagnetic ZnFe2O4 thin films on SrTiO3 single crystals with highly tunable electrical conductivity

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Abstract

The electrical conductivity of zinc ferrite (ZFO) thin films can be tuned over 7 orders of magnitude. The conductivity is thermally induced with two activation energies around 40–55 meV and 70–130 meV. Doping of the ZFO films with 1 at% Si or Ge further increases the conductivity. The magnetic hysteresis shows coercive fields of about 0.01 T and high saturation magnetization up to 300 emu/cm3 at 300 K. The electronic Hall mobility and carrier concentration at high magnetic fields are about 0.07 cm2/V s and 1.2 × 1020 cm–3 at room temperature, respectively, which indicates a hopping dominated conductivity. The out-of-plane orientation of the ZFO films fabricated by pulsed laser deposition is (001) on SrTiO3(001) and (111) on SrTiO3(111).

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The resistivity of ZnFe2O4 thin films on SrTiO3 is tunable over 7 orders of magnitude by the PLD growth parameters and doping with group IV elements.

(© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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