Interelectronic repulsions versus lanthanide contraction: a challenge within the high-pressure synthesis of the MSr ₂RECu ₂O ₈ family of compounds

Abstract

More than 20 materials of the family of compounds MSr ₂RECu ₂O ₈, loosely called ‘metalo-cuprates’, have been prepared and characterized. Working in the synthesis of these solids, most of them prepared at high pressure and high temperature, one realizes that the optimum pressure conditions needed for their adequate formation bear a remarkable Gaussian correlation with the rare earth size and do not follow the classic lanthanide contraction so often observed in the chemistry of those elements.

Keywords:

• high pressure
• rutheno-cuprates
• size–pressure relations
• lanthanide contraction

Acknowledgements

We thank Dr Jose Manuel Gallardo Amores for help with the sample preparation at LABCOAP (http://www.ucm.es/info/labcoap/index.htm). High-pressure experiments (Ir-Ho and Ir-Yb1212) were performed at the Bayerisches Geoinstitut under the EU ‘Research Infrastructures: Transnational Access Programme (Contract No. 505320 (RITA)-High Pressure)’ program.