Thermal and Electronic Transport Properties and Two-Phase Mixtures inLa5/8−xPrx

Abstract

We measured thermal conductivity kappa, thermoelectric power S, and electric conductivity sigma of La(5/8-x)Pr(x)Ca(3/8)MnO3, showing an intricate interplay between metallic ferromagnetism (FM) and charge ordering (CO) instability. The change of kappa, S, and sigma with temperature (T) and x agrees well with the effective medium theories for binary metal-insulator mixtures. This agreement clearly demonstrates that with the variation of T as well as x, the relative volumes of FM and CO phases drastically change and percolative metal-insulator transition occurs in the mixture of FM and CO domains.

Metal-Insulator Transition Induced by Short Range Magnetic Ordering in Mono-layered Manganite

“…24 However, we have not seen any other magnetic signals in the entire temperature range besides the weak FM transition near 130 K. Second, the perovskite phase La 1-x Sr x MnO 3 that considers as the most likely impurity shows the onset of FM ordering typically in the higher temperature range above 200 K. 24 Finally, the M-I transition cannot be induced by the impurity or inter-grown phases alone because a minimal volume fraction to connect percolation path is at least about 20%. 26 Another important feature to be addressed is that neither weak FM ordering nor M-I transition has been observed in single crystal of the mono-layered manganite. This remarkable discrepancy might be due to the interstitial oxygen only present in the polycrystalline sample.…”

Flux phase as a dynamic Jahn-Teller phase: Berryonic matter in the cuprates

“…Baberski, et al 114 find a very similar suppression of κ in the cuprates, but always at the LTT transition. Figure 14 compares the thermal conductivity near the LTT transition in LSCO:Nd [ 114] (b) with that of the charge ordering transition in a manganite 115 (a), suggesting an intimate connection between the LTT and charge ordering transitions. In the absence of long range LTT order, κ is suppressed over the full temperature rangethis is found both for pure LSCO and for the RE substituted materials, for x > 0.17.…”

“…14. Thermal conductivity of (a) La0.525Pr0.1-Ca0.375MnO3 [ 115], and (b) La1.28Nd0.60Sr0.12CuO4 [ 114].…”

Staircase-like metamagnetic transitions in phase-separated manganites: Influence of thermal and mechanical treatments

“…In lots of these materials, a phenomenon of electronic phase separation occurs, which influences considerably the physical properties [2][3][4][5][6][7][8][9][10][11].…”