Colossal Electroresistance Research Articles

Temperature dependence of colossal electro-resistance of Pr 0.7Ca 0.3MnO 3 thin films

The electronic conduction through a Pr 0.7Ca 0.3MnO 3 thin film is investigated by measurements using dc and pulsed bias. Pr 0.7Ca 0.3MnO 3 films sandwiched by electrodes exhibit two stable resistance states by means of applying voltage pulses. Both of the states show semiconducting behavior. The ratio of the two resistance states induces a colossal electro-resistance (CER) effect greater than 1000%. The CER behavior is seen in the temperature range of 300 K down to 150 K. The observed conduction characteristics exhibit the space-charge-limited-current effect, and the switching behavior can be ascribed to a carrier trapping/detrapping of the trap sites in the perovskite manganite.

Colossal electroresistance of aPr0.7Ca0.3MnO3thin film at room temperature

The electronic conduction through a ${\mathrm{Pr}}_{0.7}{\mathrm{Ca}}_{0.3}\mathrm{Mn}{\mathrm{O}}_{3}$ thin film is investigated by measurements using dc and pulsed biases. Semiconducting ${\mathrm{Pr}}_{0.7}{\mathrm{Ca}}_{0.3}\mathrm{Mn}{\mathrm{O}}_{3}$ films sandwiched by electrodes show both hysteretic and asymmetric behaviors in current-voltage characteristics. The observed conduction characteristics exhibit the space-charge-limited-current effect, and the hysteretic behavior can be ascribed to a carrier trapping and detrapping of the trap sites in the manganite. The hysteresis induces a colossal electroresistance (CER) of more than 5000% at room temperature. The CER ratio is independent of the duration time of pulses from an infinite (dc) down to $150\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$, indicating that the carrier filling of all the traps can be completed within a short time.

Anomalous current–voltage characteristics and colossal electroresistance of amorphous carbon film on Si substrate

Amorphous carbon film (a-C film) was deposited on n-Si substrate by pulsed-laser deposition at room temperature. The electrical transport properties of a-C film/n-Si were investigated by current–voltage (I–V) measurements at various temperatures. The results indicate that the resistance of a-C film/n-Si is controlled by the applied electric current. The most important result is that when the value of the electric voltage is larger than a threshold, the current increases abruptly to a very large value, and the value of the voltage threshold decreases with increasing temperature. Correspondingly, the colossal electroresistance (ER) was achieved in the temperature range measured. The ER reaches −84.5% and −99.5% at T=310K and 170K, respectively. The mechanism of the I–V characteristics may be understood by an energy band structure of a-C film/n-Si. The anomalous I–V characteristics and colossal ER should be of interest for various applications such as field-effect devices.

Electric current-induced first-order effects on the insulator–metal transition and the colossal electroresistance in rare-earth manganates

Passing electric currents through a single crystal of La0.77Ca0.23MnO3 causes a marked decrease in the temperature of the insulator–metal transition, TIM, the TIM decreasing with increasing current. The transition exhibits thermal hysteresis, the magnitude of which increases with an increase in applied current. Large negative electroresistance is observed close to room temperature while large positive electroresistance occurs at low temperatures. Similar results are observed with La0.9MnO3 as well.