High-pressure synthesis and sequential ferrimagnetic ordering and spin glass transition of a Fe/Ru disordered quadruple perovskite CeCu₃Fe₂Ru₂O₁₂

We successfully prepared a A-site-ordered quadruple perovskite oxide CeCu 3 Fe 2 Ru 2 O 12 by using a high-pressure method (10 GPa, 1400 K). The compound crystallizes in the Im 3 space group, with A-site ordering of Ce and Cu ions in a ratio of 1:3, but B-site disordered distribution of Fe and Ru ions. Bond-value-sum calculations and X-ray photoelectron spectroscopy measurement manifest that the charge distribution is Ce 3.5+ Cu 2+ 3 Fe 3+ 2 Ru 4.25+ 2 O 12 . A ferrimagnetic phase transition occurs at T C = 73.6 K followed by a spin glass behavior at 50.3 K consistent with the conventional dynamical scaling power law. Electrical transport measurement shows that the intrinsic electrical behavior is semiconducting and the resistivity obey the adiabatic small-polaron model. The specific heat follows a T 2 law instead of traditional phonon-dominated T 3 behavior implying a finite energy gap in the excitation spectrum.