Extending the n = 2 Ruddlesden–Popper solid solution La2–2xSr1 + 2xMn2O7 beyond x= 0.5: synthesis of Mn4+–rich compounds

Abstract

Reported herein are the synthesis and room temperature crystal structures of the heretofore unknown, metastable manganites La_2–2xSr_{1 + 2x}Mn₂O_{7 + δ} (0.5 ⩽ x ⩽ 0.9) via high temperature (T = 1650 °C) quenching followed by low temperature (T = 400 °C) annealing to fill oxygen vacancies; this approach enables access to the electronic, magnetic, and structural properties of previously unexplored compositions in this important CMR system.