Author(s)

Ekaterine Chikoidze¹, Yves Dumont¹, Elena Popova¹, Niels Keller¹, Andrey Shumilin², Veniamin Kozub², Benedicte Warot-Fonrose³

¹Groupe d’Etudes de la Matière Condensée (GEMaC), Université de Versailles St-Quentin en Yvelines—CNRS, Versailles, France.
²A. F. IoffePhysico-Technical Institute, Russian Academy of Sciences, St. Peterbourg, Russia.
³CEMES-CNRS, Toulouse, France.

Electronic transport properties of magnetically disordered R(-3)c phase Fe_1.5Ti_0.5O_3-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 0.1μ_B/formula compared to the theoretical value of 2μ_B/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.

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

Chikoidze, E. , Dumont, Y. , Popova, E. , Keller, N. , Shumilin, A. , Kozub, V. and Warot-Fonrose, B. (2014) Large Room Temperature Magneto-Resistance in Magnetically Disordered Fe_1.5Ti_0.5O_3-δ Thin Films. World Journal of Condensed Matter Physics, 4, 250-261. doi: 10.4236/wjcmp.2014.44028.