Eur. Phys. J. B 50, 587-592 (2006)
https://doi.org/10.1140/epjb/e2006-00178-9

Intrinsic tunnelling effects in self-doped La_0.89MnO₃ single crystals

¹ Department of Physics, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beer Sheva, Israel
² Donetsk Physical and Technical Institute, National Academy of Sciences of Ukraine, 83114 Donetsk, Ukraine
³ Moscow State Steel and Alloys Institute, 119991 Moscow, Russia

Corresponding author: ^a jung@bgumail.bgu.ac.il

Received: 23 November 2005
Revised: 20 February 2006
Published online: 17 May 2006

Abstract

Transport properties of self-doped La_0.89MnO₃ single crystals with Néel temperature of T_N ≈139 K have been investigated in wide temperature range 10–300 K. Data suggests that current at low temperature is conducted through a strongly temperature-dependent, but almost bias independent channel operating in parallel with a bias controlled but temperature independent channel. The first channel is associated with transport across an insulating antiferromagnetic matrix while the latter one represents tunnel conductivity through intrinsic tunnel junctions appearing due to interruption of conducting percolating paths by phase separated insulating inclusions. Tunnel character of the conductivity manifests itself in nonlinear current-voltage characteristics and appearance of a zero-bias anomaly in the form of a prominent conductance peak in the vicinity of zero bias. Zero bias anomaly and V-shaped characteristics of the differential conductance at high voltages are ascribed to the formation of local magnetic states in the insulating region of the tunneling junction.