Electron Paramagnetic Resonance Linewidths and Lineshapes for the Molecular Magnets Fe8 and Mn12

Kyungwha Park; M. A. Novotny; N. S. Dalal; S. Hill; P. A. Rikvold

doi:10.1063/1.1456424

Electron Paramagnetic Resonance Linewidths and Lineshapes for the Molecular Magnets Fe8 and Mn12

Condensed Matter 2009-11-07 v2

Authors: Kyungwha Park , M. A. Novotny , N. S. Dalal , S. Hill , P. A. Rikvold

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Abstract

We study theoretically Electron Paramagentic Resonance (EPR) linewidths for single crystals of the molecular magnets Fe $_8$ and Mn $_{12}$ as functions of energy eigenstates $M_s$ , frequency, and temperature when a magnetic field along the easy axis is swept at fixed excitation frequency. This work was motivated by recent EPR experiments. To calculate the linewidths, we use density-matrix equations, including dipolar interactions and distributions of the uniaxial anisotropy parameter $D$ and the Land\'{e} $g$ factor. Our calculated linewidths agree well with the experimental data. We also examine the lineshapes of the EPR spectra due to local rotations of the magnetic anisotropy axes caused by defects in samples. Our preliminary results predict that this effect leads to asymmetry in the EPR spectra.

Keywords

Electron Paramagnetic Resonance molecular magnets linewidth density-matrix equations lineshape

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@article{arxiv.cond-mat/0111589,
  title  = {Electron Paramagnetic Resonance Linewidths and Lineshapes for the Molecular Magnets Fe8 and Mn12},
  author = {Kyungwha Park and M. A. Novotny and N. S. Dalal and S. Hill and P. A. Rikvold},
  journal= {arXiv preprint arXiv:cond-mat/0111589},
  year   = {2009}
}

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2001 MMM conference

Electron Paramagnetic Resonance Linewidths and Lineshapes for the Molecular Magnets Fe8 and Mn12

Abstract

Keywords

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