Chemistry and Physics Faculty Proceedings, Presentations, Speeches, Lectures

Searching for Superconductors in Complex Mixtures: Solid-state Synthesis, Structural Analysis, and Physicochemical Characterization (Invited)

Event Name/Location

Electronic Materials and Applications, Orlando, Florida, January 18-20, 2017

Presentation Date

1-18-2018

Document Type

Conference Proceeding

ORCID ID

0000-0001-7825-8667

Description

Our search for new high-temperature superconductors is guided by common structural features and compositions that are shared by superconductors in a variety of material families. Since superconductivity is often ascribed to specific layers within a crystal structure, new materials with layered structures are targeted using conventional high-temperature solid-state synthesis. Here, Magnetic Field-Modulated Microwave Spectroscopy (MFMMS), which can be used to selectively detect superconducting transitions with high sensitivity and selectivity, is used to search for signatures of superconductivity in polycrystalline powders. Magnetic Field-Modulated Microwave spectra of RE-M-O (RE = rare earth; M = transition metal) samples exhibited responses that are akin to those from superconductors, such as YBCO. The structures and phase compositions were analyzed via X-ray powder diffraction (XRPD). In some cases, high resolution synchrotron XRPD data was used to assess low-weight fraction phases in samples that gave rise to peak-like responses in MFMMS data. Rietveld refinements using high-resolution XRPD data allowed the phases in complex mixtures to be identified and quantified. Zero-field cooled (ZFC) and field-cooled (FC) vibrating sample magnetometry (VSM) was used to evaluate magnetic properties.

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