Nonlinear current-voltage behavior and electrically driven phase transition in charge-frustrated LuFe ₂ O ₄

Abstract

Electric transport measurements of the charge frustrated LuFe 2 O 4 , in which the charge ordering (CO) and electronic ferroelectricity are found, reveal strong nonlinear electric conduction upon application of electrical field in both single crystalline and polycrystalline samples. The threshold electric fields (E t ) in single crystalline LuFe 2 O 4 are estimated respectively to be about 60V/cm and 10V/cm with E parallel and perpendicular to the c-axis direction. Experimental measurements also demonstrate that the I-V nonlinearity increases quickly with lowering temperature. Furthermore, our in-situ TEM investigations evidently reveal that the nonlinear I-V behavior is intrinsically in correlation with a current driven charge ordering insulator-metal transition, and the applied electrical field triggers a visible CO collapse recognizable as the fading of satellite spots of the CO modulations. PACS number(s): 75.47. Lx, 74.25.Jb

Suppression of the current leakage in charge ordered Lu2Fe2Fe1−xMnxO7 (<x≤0.86)

“…5 The equal numbers of Fe 2+ and Fe 3+ in a W layer can be ordered and result in ferroelectric polarizations as extensively studied in previous literatures for the LuFe 2 O 4 ͑n =0͒ phase. [6][7][8] Ferroelectric measurements of Lu-Fe-O materials often reveal hysteresis loops ͑so-called P-E loop͒ with notable instability caused by the visible conductivity leakage and dynamic CO fluctuation in this kind of layered materials. 9 MnO ͑99%͒ were fully mixed in an agate mortar.…”

Detection of low ppm carbon monoxide with charge ordered LuFe 2 O 4 gas sensor – A novel sensing mechanism

“…The sharp non-linear transition in the current density beyond a threshold electric field (E t ) of 8 Vcm -1 highlights the intrinsic charge ordering within the system. The electric field at which the abrupt change in transport behaviour is observed lies well below the standard breakdown field (10 7 Vcm -1 ) of a band insulator and is comparable to those observed in charge order manganite systems [18]. The nonlinear coefficient (α) can be calculated from the relation I=kV α and is estimated as 32 within the current density of 0.021 Acm -2 and 9.01 Acm -2 .…”

Electric-field effects in resistive oxides: facts and artifacts

“…[14] by solving a second order differential equation of heat conduction. Here E is a constant but J is a function of the radius; the result is better expressed in terms of current ( J-E characteristics of LuFe 2 O 4 that exhibit current runaway, as seen in figure 4 for R L →0, have been reported in several articles [15] and have been interpreted as a phase transition induced by the electric-field. With decreasing temperatures, the vertical portions of their characteristics are shifted to lower fields, thus in favor of current runaway in the regime of thermal NDR.…”

“…With decreasing temperatures, the vertical portions of their characteristics are shifted to lower fields, thus in favor of current runaway in the regime of thermal NDR. In reference [15] the thermal runaway was limited by restricting the current to finite values (equivalent to a small load resistance). Our pulsed J-E characteristics of LuFe 2 O 4 are perfectly linear up to ~480 V/cm (far higher than the maximal fields in reference [15]).…”

“…In reference [15] the thermal runaway was limited by restricting the current to finite values (equivalent to a small load resistance). Our pulsed J-E characteristics of LuFe 2 O 4 are perfectly linear up to ~480 V/cm (far higher than the maximal fields in reference [15]). We used single pulses much shorter than theirs (1 -4 msec duration); for long (100 msec) constant current pulses the voltage drops between probes exhibit strong time dependence (see figure 3 in reference 9) caused by selfheating.…”