Negative Magnetization Phenomena in A-Site Columnar-Ordered Quadruple Perovskites Ce2MnM(Mn2Sb2)O12 with M = Mn and Zn

A phenomenon of magnetization reversal in response to an applied magnetic field is very common and forms the basis of magnetic memories. In contrast, the phenomenon of magnetization reversal in response to a temperature change is rarer. In this work, we demonstrated a pronounced negative magnetization effect (NME) during field-cooled measurements in small magnetic fields in members of the A-site columnar-ordered quadruple perovskites, Ce₂MnM(Mn₂Sb₂)O₁₂ with M = Mn and Zn, which were prepared by a high-pressure, high-temperature method at about 6 GPa and about 1600 K. Their crystal structures at room temperature were investigated with synchrotron X-ray powder diffraction data. Both compounds crystallize in space group P4₂/n (No. 86) with full rock-salt ordering of Mn and Sb at the B sites. Lattice parameters are a = 7.84545(1) and c = 7.95529(2) Å for M = Mn and a = 7.81270(1) and c = 7.94100(1) Å for M = Zn. The bond-valence sum analysis and the charge balance suggest that cerium is present in the oxidation state of +3. They show one magnetic transition at T_C = 52 K with the compensation point near 20 K for M = Mn, and at T_C = 34 K with the compensation point near 29 K for M = Zn. A robust, intrinsic NME was also observed on zero-field-cooled curves when measured in small magnetic fields. The NME could originate from its ferrimagnetic structures.