Pulsed versus DC I-V characteristics of resistive manganites

TL;DR

This study compares pulsed and DC I-V measurements of various manganites, revealing that DC measurements often misrepresent true conductivity due to artifacts like negative differential resistance and hysteresis.

Contribution

It demonstrates that pulsed I-V techniques provide more accurate conductivity measurements than traditional DC methods in charge-ordered manganites.

Findings

DC I-V shows negative differential resistance and hysteresis at high currents.

Pulsed I-V reveals ohmic or moderate nonohmic behavior.

DC measurements can be misleading due to measurement artifacts.

Abstract

We report on pulsed and DC I-V characteristics of polycrystalline samples of three charge-ordered manganites, Pr_{2/3}Ca_{1/3}MnO_3, Pr_{1/2}Ca_{1/2}MnO_3, Bi_{1/2}Sr_{1/2}MnO_3 and of a double-perovskite Sr_2MnReO_6, in a temperature range where their ohmic resistivity obeys the Efros-Shklovskii variable range hopping relation. For all samples, the DC I(V) exhibits at high currents negative differential resistance and hysteresis, which mask a perfectly ohmic or a moderately nonohmic conductivity obtained by pulsed measurements. This demonstrates that the widely used DC I-V measurements are usually misleading.