Analyzing Magnetic Molecules Using TDR

ORAL

Abstract

Since the early nineties, much interest has grown in the field of magnetic molecules due to the fact that at suitably low temperatures, intermolecular interactions can be ignored. As a result, studying crystalline samples can be reduced to analyzing the discrete spectrum of magnetic energy levels within an individual molecule. As the size and complexity of magnetic molecules continues to grow, we see that low temperature DC magnetization measurements are restricted to regions of ground state level crossings, demanding a more detailed experimental technique. However, using a tunnel diode resonator (TDR) to measure the dynamic magnetic susceptibility in the millikelvin range, we can probe the magnetic spectrum in both the ground state and low-lying excited states. The TDR technique has recently been used to investigate the magnetic molecules Cr$_{12}$Cu$_{2}$ and Cr$_{10}$Cu$_{2}$. When compared with theoretical quantum Monte Carlo (QMC) simulations, we find the TDR results to be in excellent agreement with the predicted energy spectrum. This demonstrates that the QMC model can be a valuable quantitative tool for predicting properties of magnetic molecules; as well, the TDR technique is demonstrated to be a unique and powerful tool for analyzing the magnetic spectrum.

–

Authors

  • Steven Yeninas

    Iowa State University/Ames Laboratory

  • Ruslan Prozorov

    Iowa State University/Ames Laboratory

  • Michael Turner

    Illinois Institute of Technology, Bettendorf High School, Bettendorf, IA, Mississippi Bend Area Education Agency, Bettendorf, IA, Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA, Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA, Max-Planck-Institut fuer Mikrostrukturphysik, Halle, Germany, CNRS, Universite Lyon I, France, Freie Universitaet Berlin, Germany, University of Jyvaskila, Finaland, Iowa State University/Ames Laboratory, Materials Science Division, Argonne National Laboratory and Department of Chemistry, Northwestern University, Materials Science Division, Argonne National Laboratory, Advanced Photon Source, Argonne National Laboratory, Ames Laboratory and Iowa State University, Indiana University, Illinois State University, University of Iowa, Louisiana State University, University of Warwick, Rutherford Appleton Laboratory, Coe College, University of Northern Iowa, Iowa State University and Ames Laboratory, University of Illinois, Ames Laboratory, University of Florida, Tulane University, The Department of Physics and The James Franck Institute, The University of Chicago, J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, Department of Physics, Augustana College, Sioux Falls, SD 57197, Intense Laser Physics Theory Unit, Illinois State University, Argonne National Laboratory, Dr, Drake University, Physics Department, Ocean University of China, Qingdao, Physics Department, Southern Illinois University Carbondale, Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, USA, Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA, NEST-CNR-INFM and Scuola Normale Superiore, I-56126 Pisa, Italy, University of New Hampshire Department of Physics, University of Chicago