Faculté des sciences

High magnetic anisotropy of Fe⁺ ions in KTaO₃ and SrCl₂

Trueba, A. ; Garcia-Fernandez, P. ; Senn, F. ; Daul, Claude A. ; Aramburu, J. A. ; Barriuso, M. T. ; Moreno, M.

In: Physical Review B, 2010, vol. 81, no. 7, p. 075107

The zero-field splitting constant, D, and the gyromagnetic tensor of the off-center systems KTaO₃:Fe⁺ and SrCl₂:Fe⁺ have been explored by means of calculations based on the density-functional theory at the C4v local equilibrium geometry. The calculated D values for KTaO₃:Fe⁺ (9 cm⁻¹) and SrCl₂:Fe⁺ (53 cm⁻¹) are found to be much higher than typical figures... Plus

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    Summary
    The zero-field splitting constant, D, and the gyromagnetic tensor of the off-center systems KTaO₃:Fe⁺ and SrCl₂:Fe⁺ have been explored by means of calculations based on the density-functional theory at the C4v local equilibrium geometry. The calculated D values for KTaO₃:Fe⁺ (9 cm⁻¹) and SrCl₂:Fe⁺ (53 cm⁻¹) are found to be much higher than typical figures measured for insulating compounds containing common 3d Kramers ions with a spin S>1/2 in the ground state. This result together with the calculated g and g values concur with available experimental information. The high magnetic anisotropy derived for Fe⁺ in KTaO₃ and SrCl₂ is shown to be strongly related to the existence of a ⁴E excited state lying only at about 3000 and 600 cm⁻¹, respectively, above the ground state. Implications of present findings in the search of new molecular magnets with high values of the magnetic anisotropy are discussed in some detail.