Low-temperature transport properties of non-stoichiometric La_0.95-xSr_xMnO₃manganites

Abstract

The low-temperature specific heat and electrical resistivity of the polycrystalline non-stoichiometric manganites La 0.95−x Sr x MnO 3 have been investigated in the doping region x = 0.00-0.30. The specific heat has terms proportional to T and T 3 . The resistivity of the samples decreases as T 1/2 with increasing temperature, goes through a minimum and then increases proportionally to T 3 . The temperature T min , corresponding to the minimum of the resistivity, shifts with Sr content as T min ∼ x −2/5 .

Comment on Low-temperature transport properties of non-stoichiometric La0.95 xSrxMnO3

“…At the same time, analysis of specific heat data (typical bulk property) presented in [1] seems enough plausible.…”

“…Michalopoulou et al in [1] based on fitting of low temperature resistivity versus temperature dependencies measured only at zero magnetic field is absolutely insufficient for verification of applicability of QCC model (as well as in previous analogous attempts [3][4][5]). At the same time, analysis of specific heat data (typical bulk property) presented in [1] seems enough plausible.…”

“…Michalopoulou et al have presented in their recent paper [1] data on electrical resistivity and specific heat measured at zero external magnetic field (H) on polycrystalline non-stoichiometric La 0.95-x Sr x MnO 3 manganites in the doping region 0 ≤ x ≤ 0.3. Using numerical fittings of resistivity (ρ) vs. temperature (T) dependencies at the interval 4.2 -40 K, authors claim that the low temperature (LT) behavior of resistivity (shallow minimum and slight upturn at lowest T) may be account by 3D electron-electron interaction enhanced by disorder [2], as it was suggested previously in [3][4][5] for polycrystalline manganites.…”

“…(1) In general, A. Michalopoulou et al did not present in commented paper [1] any systematical data on conductive and magnetic properties i. Michalopoulou et al is measurement of LT ρ vs. T dependencies under external H about some Tesla -point (ii). It may be predicted certainly that GB-like minimum of resistivity will be flattened and vanished by such field [6,7,10] and almost H-independent very weak bulk-like minimum will appear (if it exists) [7].…”

Effects of ferroelectric-poling-induced strain on the quantum correction to low-temperature resistivity of manganite thin films

“…However, the phase coherence of electron waves has already been destroyed by the strong spontaneous ferromagnetic field in these compounds. 22,23 Second, Maritato et al 13 observed that the weak localization effect plays an increasingly important role in influencing the low-temperature resistivity upturn only for very thin films ͑t Ͻ 20 nm͒. For our sample, the film thickness is about 100 nm, which is relatively thick.…”