Colossal electroresistance in the ferromagnetic insulating state of single crystal $Nd_{0.7}Pb_{0.3}MnO_3$

Jain, Himanshu and Raychaudhuri, AK and Ghosh, Nilotpal and Bhat, HL (2007) Colossal electroresistance in the ferromagnetic insulating state of single crystal $Nd_{0.7}Pb_{0.3}MnO_3$. In: Physical Review B, 76 . 104408:1-7.

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Abstract

Colossal electroresistance (CER) has been observed in the ferromagnetic insulating (FMI) state of a manganite. Notably, the CER in the FMI state occurs in the absence of magnetoresistance (MR). Measurements of electroresistance (ER) and current induced resistivity switching have been performed in the ferromagnetic insulating state of a single crystal manganite of composition $Nd_{0.7}Pb_{0.3}MnO_3$. The sample has a paramagnetic to ferromagnetic (Curie) transition temperature $T_C=150 K$ and the ferromagnetic insulating state is realized for temperatures T \preceq 130 K. The colossal electroresistance, arising from a strongly nonlinear dependence of resistivity (\rho) on current density (j), attains a large value (\approx 100\%) in the ferromagnetic insulating state. The severity of this nonlinear behavior of resistivity at high current densities is progressively enhanced with decreasing temperature, resulting ultimately, in a regime of negative differential resistivity (NDR, drho/dj<0) for temperatures \preceq 25 K. Concomitant with the buildup of the ER, however, is a collapse of the MR to a small value (<20 \%) even in magnetic field, H=14 T. This demonstrates that the mechanisms that give rise to ER and MR are effectively decoupled in the ferromagnetic insulating phase of manganites. We establish that the behavior of ferromagnetic insulating phase is distinct from the ferromagnetic metallic phase as well as the charge ordered insulating phase, which are the two commonly realized ground state phases of manganites.

Item Type:	Journal Article
Publication:	Physical Review B
Publisher:	American Physical Society
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	19 Nov 2007
Last Modified:	19 Sep 2010 04:41
URI:	http://eprints.iisc.ac.in/id/eprint/12522

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