TITLE:
Large Room Temperature Magneto-Resistance in Magnetically Disordered Fe1.5Ti0.5O3-δ Thin Films
AUTHORS:
Ekaterine Chikoidze, Yves Dumont, Elena Popova, Niels Keller, Andrey Shumilin, Veniamin Kozub, Benedicte Warot-Fonrose
KEYWORDS:
PACS Numbers: 73.50.-h. Transport Processes in Thin Films, 72.20.Ee Hopping Transport, 75.47.Lx Magnetic Oxides, 75.70.Ak Magnetic Properties of Monolayers and Thin Films
JOURNAL NAME:
World Journal of Condensed Matter Physics,
Vol.4 No.4,
November
27,
2014
ABSTRACT: Electronic
transport properties of magnetically disordered R(-3)c phase Fe1.5Ti0.5O3-δ thin films epitaxially grown on Al2O3(0001)
substrates have been studied. The measured magnetization in configurations with
the magnetic field perpendicular and parallel to the film plane shows weak
values of 0.1μB/formula
compared to the theoretical value of 2μB/formula
and a strong anisotropy with no saturation in perpendicular configuration.
These properties are associated with the ato- mic scale disorder of Ti/Fe ions
along c-axis. At zero-magnetic field and within the temperature range of 80 K
to 400 K, the conduction mechanism appears to be Efros-Shklovskii variable
range hopping with a carrier localization length of ξ0= 0.86nm. Magneto-resistance (MR) is positive in
perpendicular configuration, while it is negative in parallel configuration,
with significant values of MR = 27%- 37% at room temperature at 9 Tesla. Electron localization lengths were
deduced from experiment for different external magnetic fields. The origin of magneto-resistance
observed in experiment, is discussed.