Mesoscopic transport in ultrathin films of La${}_{0.67}$Ca${}_{0.33}$MnO${}_3$

Abstract

We investigate the electrical transport in mesoscopic structures of La${}_{0.67}$Ca${}_{0.33}$MnO${}_3$ in the regime of the metal-insulator transition by fabricating microbridges from strained and unstrained thin films. We measure current-voltage characteristics as function of temperature and in high magnetic fields and with varying film thickness. For strained films, in warming from the metallic to the insulating state, we find non-linear effects in the steep part of the transition characterized by a differential resistance with a strong peak around zero applied current, and saturating at higher currents after resistance drops up to 60 %. We propose that this nonlinear behavior is associated with melting of the insulating state by injecting charge carriers, signalling the occurrence of an intervening phase which involves the formation of short range polaron correlations.

4 pages, 5 figures

References in corpus (4)

• Experimental probing of the interplay between ferromagnetism and localisation in (Ga,Mn)As
• Competing Ferromagnetic and Charge-Ordered States in Models for Manganites: the Origin of the CMR Effect
• Polaron Coherence Condensation as the Mechanism for Colossal Magnetoresistance in Layered Manganites
• Transport properties of microstructured ultrathin films of La0.67Ca0.33MnO3 on SrTiO3

Cited by in corpus (1)

• Large electric field effects on the resistance of La${}_{0.67}$Ca${}_{0.33}$MnO${}_3$ microstructures