Weak spin interactions in Mott insulating La${}_{2}$O${}_{2}$Fe${}_{2}$OSe${}_{2}$

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Weak spin interactions in Mott insulating La $_{2}$ O $_{2}$ Fe $_{2}$ OSe $_{2}$

E. E. McCabe, C. Stock, E. E. Rodriguez, A. S. Wills, J. W. Taylor, and J. S. O. Evans

Phys. Rev. B 89, 100402(R) – Published 10 March 2014

Abstract

Identifying and characterizing the parent phases of iron-based superconductors is an important step towards understanding the mechanism for their high-temperature superconductivity. We present an investigation into the magnetic interactions in the Mott insulator La $_{2}$ O $_{2}$ Fe $_{2}$ OSe $_{2}$ . This iron oxyselenide adopts a 2- $k$ magnetic structure with low levels of magnetic frustration. This magnetic ground state is found to be dominated by next-nearest-neighbor interactions $J_{2}$ and $J_{2^{'}}$ and the magnetocrystalline anisotropy of the Fe $^{2 +}$ site, leading to 2D-Ising-like spin $S = 2$ fluctuations. In contrast to calculations, the values are small and confine the spin excitations below $\sim$ 25 meV. This is further corroborated by sum rules of neutron scattering. This indicates that superconductivity in related materials may derive from a weakly coupled and unfrustrated magnetic structure.

Received 3 September 2013

DOI:https://doi.org/10.1103/PhysRevB.89.100402

Authors & Affiliations

E. E. McCabe^1,2,*, C. Stock³, E. E. Rodriguez⁴, A. S. Wills⁵, J. W. Taylor⁶, and J. S. O. Evans^1,†

¹Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
²School of Physical Sciences, University of Kent, Canterbury CT2 7NH, United Kingdom
³School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
⁴Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
⁵Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
⁶ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom

^*e.e.mccabe@kent.ac.uk
^†john.evans@durham.ac.uk

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Issue

Vol. 89, Iss. 10 — 1 March 2014

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