Metastable resistivity states and conductivity fluctuations in low-doped La1−xCaxMnO3 manganite single crystals

Abstract

Conductivity noise in dc current biased La 0.82 Ca 0.18 MnO 3 single crystals has been investigated in different metastable resistivity states enforced by applying voltage pulses to the sample at low temperatures. Noise measured in all investigated resistivity states is of 1/f-type and its intensity at high temperatures and low dc bias scales as a square of the bias. At liquid nitrogen temperatures for under bias exceeding a threshold value, the behavior of the noise deviates from above quasiequilibrium modulation noise and depends in a non monotonic way on applied bias. The bias range of nonequilibrium 1/f noise coincides with the range at which the conductance increases linearly with bias voltage. This feature is attributed to a broad continuity of states enabling indirect inelastic tunneling across intrinsic tunnel junctions. The nonequilibrium noise has been ascribed to indirect intrinsic tunneling mechanism while resistivity changes in metastable states to variations in the energy landscape for charge carriers introduced by microcracks created by the pulse procedures employed.

Noise Features of Metastable Resistivity States in La0.86Ca0.14MnO3 Manganite Single Crystal

“…The dependence of n on temperature and bias is complicated and related to changes in the transport mechanisms, as discussed in details in our earlier publications, see e.g. [7][8][9]. Nevertheless, we can compare the ratio of noise volumes with the ratio of the resistivities in these states À À À see Fig.…”

ESR Study of (La,Ba)MnO3/ZnO Nanostructure for Resistive Switching Device

“…Such complexity of the properties of perovskite manganites has become the point of attraction for a vast number of researchers around the world [2, 5, 6]. It is expected that this class of materials will create the foundation for various applications, such as low-field magnetoresistance sensors, resistive switching devices, and others [6, 7]. …”

Zero-bias anomalies in low-doped La 1−x Ca x MnO 3 manganite single crystals

“…We have previously shown that temperature and bias dependence of resistivity of single-crystalline La 1−x Ca x MnO 3 samples doped at x = 0.18 and/or x = 0.20 can be well described using the model [10] of indirect inelastic tunnelling [3,8]. We have also used a single junction approach to explain peculiarities of noise characteristics and metastable resistivity states in low-doped manganite crystals [11][12][13][14].…”