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Search of phase transitions using a helical cavity susceptometer

ORAL

Abstract

The synthesis of new quantum materials requires development of new experimental techniques for their characterization. Phase transitions (PT) convey “materials’ fingerprints”, however, a search of PTs implies complex and unique approaches, which are typically costly and time-demanding. We designed and built an inexpensive apparatus which enables detecting PTs of different types: normal-superconductor, metal-insulator, para-ferromagnet. The apparatus consists of a cylindrical helical cavity which is installed on a custom-made inset for a QD cryostat. A phase locked loop maintains a fundamental resonance mode at sub-GHz frequency, while the ambient temperature and magnetic field are varied (2-400 K, 0-90 kOe, respectively). It enables tracing the change in conductivity and magnetic permeability with very high sensitivity even in a 10-8 cc sample. We will demonstrate that device is extremely useful for studying PT phenomenon in low-dimensional magnetic heterostructures. Additionally, data for a few superconducting samples will be presented.

Presenters

  • Pavel N. Lapa

    University of California, San Diego

Authors

  • Pavel N. Lapa

    University of California, San Diego

  • George Kassabian

    University of California, San Diego

  • Nicolas M Vargas

    Department of Physics, University of California, San Diego, University of California, San Diego, Department of Physics, University of California San Diego

  • Ivan Schuller

    University of California, San Diego, Dept. of Physics and Center for Advanced Nanoscience, UCSD, La Jolla, CA, USA, Physics Department, University of California, San Diego, Department of Physics, University of California, San Diego