Eur. Phys. J. Special Topics 169, 141-145 (2009)
https://doi.org/10.1140/epjst/e2009-00984-9

Effect of the chemical pressure on bimagnons in antiferromagnetic insulators: CacuO₂ and BacuO₂ studied with Cu-L₃ resonant inelastic X-ray scattering

¹ European Synchrotron Radiation Facility, BP. 220, 38043 Grenoble Cedex, France
² Institute-Lorentz for Theoretical Physics, Universiteit Leiden, PO Box 9506, 2300 RA Leiden, The Netherlands
³ CNR-INFM Coherentia, Dipartimento di Scienze Fisiche, Università di Napoli “Federico II", Complesso di Monte S. Angelo, via Cinthia, 80126 Napoli, Italy
⁴ CNR-INFM-Coherentia and Dipartimento di Ingegneria Meccanica, Università di Roma Tor Vergata, via del Politecnico 1, 00133 Roma, Italy
⁵ Dipartimento di Fisica “E.R. Caianiello," Università di Salerno, 84081 Baronissi, Salerno,, INFM-CNR, Baronissi (SA), Italy
⁶ INFM-CNR-Coherentia, Dip. di Fisica, Politecnico di Milano, p. Leonardo da Vinci 32, 20133 Milano, Italy
⁷ INFM-CNR-SOFT, Dip. di Fisica, Politecnico di Milano, p. Leonardo da Vinci 32, 20133 Milano, Italy
⁸ Institute for Molecules and Materials, Radboud Universiteit Nijmegen, PO Box 9010, 6500 GL Nijmegen, The Netherlands

Corresponding author: vbisogni@esrf.fr

Abstract

Substitution of Ca with Ba in CaCuO₂ increases the lattice parameter which in turn modifies all interactions between the constituent ions. Here we study the effect on the bimagnon propagating in the Cu-O planes as seen with Resonant Inelastic X-ray Scattering at the Cu-L₃ peak. The bimagnon energy is reduced by a factor of 0.67 ±0.06 while its spectral weight decreases at least by a factor of 0.5. This scaling is understood from the dependence on superexchange, which is linear in the former case and quadratic in the second. Moreover the scaling of the bimagnon energy can be understood from the distance dependence of the transfer integrals.