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Electroresistance and magnetoresistance of polycrystalline La0.67Ca0.33MnO3 films
|Oleg Kiprijanovič , Andžej Lučun , Steponas Ašmontas , Fiodoras Anisimovas , Renata Butkute , Andrius Maneikis , Algirdas Sužiedėlis , Bonifacas Vengalis|
Semiconductor Physics Institute, A.Gostauto 11, Vilnius LT-2600, Lithuania
Polycrystalline La0.67Ca0.33MnO3 films were grown by pulsed laser deposition technique on 100-faces of a cleaved of MgO crystal demonstrating arrays of nanoscale defects. The films with average thickness of about 150 nm showed a granular structure of submicron size (as found by AFM) and exhibited paramagnetic-ferromagnetic phase transition temperature at 145-220 K. Ag electrodes were deposited onto the masked tape-like films with 1 mm in width to perform electrical and magnetic field-dependent electrical resistance measurements. Either dc current or rectangular shape electric pulses of nanosecond time duration and repetition rate of 100 Hz were used for the investigations. Influence of electrical field on film transport properties was investigated systematically at various temperatures, various applied magnetic field and using a gap between the adjacent patterned electrodes ranging from 10 μm to 360 μm. The highest values of both negative magnetoresistance (CMR) and electroresistance (ER) of the films were indicated in the vicinity of their characteristic temperature Tm corresponding to a maximum value of low-field resistance. Slight shift of the resistance-vs-temperature curve R=f(T) to higher temperatures was indicated for the films with applied magnetic field. However, our measurements using nanosecond pulses revealed absence of any shift of the characteristic peak (at Tm) with applied strong electrical field. Furthermore, occurrence of additional resistance anomaly at T>Tm has been indicated in a case of strong pulsed electrical field. Additional investigations are in progress to reveal correlation between ER and CMR and explain the origin of the observed high field resistance anomaly.
Presentation: Poster at E-MRS Fall Meeting 2006, Symposium K, by Andžej Lučun
See On-line Journal of E-MRS Fall Meeting 2006
Submitted: 2006-05-15 18:30 Revised: 2009-06-07 00:44