PREPARAZIONE ED INVESTIGAZIONE DI SUPERCONDUTTORI AD ALTA TEMPERATURA IRON-BASED

Responsabili di progetto

Massimiliano Polichetti, Elena Nazarova

Accordo

BULGARIA - BAS - Bulgarian Academy of Sciences

Bando

CNR/BAS 2013-2015

Dipartimento

Materiali e Dispositivi

Area tematica

Scienze fisiche e tecnologie della materia

Stato del progetto

Nuovo

Proposta di ricerca

The discovery of new iron-based superconducting families (LnFeAsOF –abbreviated as 1111; AEFe2Se2-122; AFeAs-111; Fe(Se,Te)-11 and Sr2VO3FeAs-21311) put important questions in front of the condensed matter research. These compounds represent a second class of high –Tc materials. The coexistence of magnetic order and most probably non conventional superconductivity in them raised the question for the mechanism of superconducting pairing. The transformation of parent compound, usually antiferromagneticaly ordered by pressure (internal or chemical) to the superconducting one shows the similarities with the cuprates. Discovering of superconductivity in FeSe having simplified structure compared to the iron pnictides with no toxic elements also attracted great interest. Intercalation with additional metal layer (K, Rb, Cs) between FeSe layers increases the Tc up to about 30 K.  In our research we plan to study the magnetic behavior of these materials, starting from their fabrication and structural characterization, and using magnetic AC and DC measurements and analysis techniques, in order to determine the characteristics of vortex dynamics in these materials and to analyze their similarities and differences respect to analogous peculiarities found in cuprates. To this aim, we will make use of competences and facilities present at CNR, at the University of Salerno and at the Bulgarian Academy of Sciences of Sofia (Bulgaria), as well as of the collaborations already activated with the Institute of Low Temperatures and Structural Research in Wroclaw (Poland), and with the Leibniz institute for Solid State Physics and Materials Research in Dresden (Germany)

Obiettivi della ricerca

The goals of the collaboration is the preparation of superconducting Iron- based sample, and in particular of FeSe compounds, their structural and morphological characterization, and the analysis of the magnetic properties in DC and AC, to extract information about the mixed state and the vortex dynamics. The DC properties will be analyzed by using the vibrating sample magnetometry technique in high field, whereas the AC response will be studied by AC magnetic susceptibility measurements as function of various external parameters like temperature, amplitude and frequency of the AC field, intensity of an eventual additional DC field. In particular, the AC properties will be analyzed by means of a combined study of the response of the real and imaginary parts of both the first and the third harmonic components of the AC magnetic susceptibility.

Ultimo aggiornamento: 20/04/2024