Log-T divergence and Insulator-to-Metal Crossover in the normal state resistivity of fluorine doped SmFeAsO1-xFx

S. C. Riggs; J. B. Kemper; Y. Jo; Z. Stegen; L. Balicas; G. S. Boebinger; F. F. Balakirev; Albert Migliori; H. Chen; R. H. Liu; X. H. Chen

arXiv · 0806.4011

Log-T divergence and Insulator-to-Metal Crossover in the normal state resistivity of fluorine doped SmFeAsO1-xFx

S. C. Riggs·J. B. Kemper·Y. Jo·Z. Stegen·L. Balicas·G. S. Boebinger·F. F. Balakirev·Albert Migliori·H. Chen·R. H. Liu·X. H. Chen

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Abstract

We report the resistivity of a series of fluorine-doped SmFeAsO1-xFx polycrystalline superconductors in magnetic fields up to 60T. For underdoped samples (x < 0.15), the low temperature resistive state is characterized by pronounced magneto-resistance and a resistive upturn at low temperatures. The "insulating behavior" is characterized by a log-T divergence observed over a decade in temperature. In contrast, the normal state for samples with doping x > 0.15 display metallic behavior with little magnetoresistance, where intense magnetic fields broaden the superconducting transition rather than suppress Tc. The location of the insulator-to metal crossover coincides with the reported suppression of the structural phase transition (SPT)in the phase diagram for SmFeAsO1-xFx series.

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S. C. Riggs, J. B. Kemper, Y. Jo, Z. Stegen, L. Balicas, G. S. Boebinger, F. F. Balakirev, Albert Migliori, H. Chen, R. H. Liu, X. H. Chen. 2008-06-25. Log-T divergence and Insulator-to-Metal Crossover in the normal state resistivity of fluorine doped SmFeAsO1-xFx. https://arxiv.org/abs/0806.4011

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