Transport properties in parent compounds of 1111-Iron Based Superconductors

Date

Dec 3, 2015

Time

1:00 PM - 2:00 PM

Speaker

Federico Caglieris

Affiliation

Department of Physics, University of Genova

Language

en

Main Topic

Materialien

Other Topics

Materialien, Physik

Host

Christine Malbrich

Description

Abstract Since their discovery in 2008 Iron Based Superconductors (IBS) have captured the attention of the scientific community not only due to their exceptional superconducting properties but also for fundamental issues concerning the nature of unconventional superconductivity. Indeed the proximity of antiferromagnetism and superconductivity in their phase diagram as a function of doping indicates spin fluctuations as the main responsible of the pairing mechanism, but many questions are still open. In this work I present a study of the transport properties of the parent compounds of the 1111-family of IBS whose chemical composition is REFeAsO (RE=rare earth). These parent compounds are multiband, quasi-2D materials, which undergo an antiferromagnetic transition below a Neel temperature TN of about 140 K while superconductivity is induced through electron doping (i.e. by F-substition on the site of O). Resistivity, magnetoresistivity and Hall effect have been measured and combined together in order to get information about the band parameters (charge carrier densities and mobilities). Moreover resistivity measurements on single crystals at very low temperatures are characterized by the appearance of Shubnikov the Haas oscillations, an original observation in these compounds. Thermoelectric properties (Seebeck and Nernst effects) have been measured up to high magnetic fields. There are sensitive probes of charge carriers-spin fluctuations coupling in a magnon drag framework and a simple theoretical model has been proposed to confirm this scenario.

Links

• Seminars at the IFW

Last modified: Dec 3, 2015, 8:50:06 AM