CdCu₃Ti₃MnO₁₂₋<i>_δ</i> quadruple perovskites: High‐pressure synthesis, structural, magnetic, and dielectric properties

Abstract The incorporation of magnetic transition metal ions at the B‐site, or substitution‐induced distortions even by non‐magnetic cations, can introduce concurrent structural and exchange‐interaction complexities. The present work reports on the structural, dielectric, and magnetic properties of CdCu 3 Ti 3 MnO 12− δ (CCTMO) quadruple perovskite oxide ceramics synthesized under high‐pressure and high‐temperature (HP–HT) conditions (6 GPa, 1173 K, 1273 K, and 1373 K). X‐ray diffraction data and their Rietveld refinements reveal that the CCTMO oxides crystallize in a cubic CdCu 3 Ti 4 O 12 ‐type quadruple perovskite structure with space group of Im . X‐ray photoelectron spectroscopy spectra verify that the valence states can be represented as Cd 2+ Mn 3+ O 12− δ in an ionic model. Dielectric spectroscopy unveiled relaxor‐like dielectric behaviors for all the samples (sintered at 1173, 1273, and 1373 K) with thermal activation energies of 0.39, 0.42, and 0.45 eV, respectively. The movements of the singly ionized oxygen vacancies () are responsible for the temperature‐dependent relaxor‐like dielectric behaviors observed between 173 and 500 K. At 10 5 Hz, the CCTMO samples sintered at 1173 K had the dielectric constant ( ε r ) value of ∼119 and dielectric loss (tan δ ) value of 0.82, whereas the ε r = 81 and tan δ = 0.72 for the CCTMO samples sintered at 1373 K. Ferromagnetic (FM) behavior was observed at 2 K in these CCTMO samples with saturation magnetizations of 2.90–3.14 μ B /f.u., whereas paramagnetic behavior appeared at 300 K. The Curie–Weiss fittings of the inverse magnetic susceptibilities ( χ −1 ) versus temperature curves yielded the positive θ P values of 143–179 K, indicating the predominant FM interactions despite of the antiferromagnetic ground states. The present work demonstrates that the coexistence of competing magnetic orders and relaxor‐like dielectric behavior in the CCTMO compounds promotes them to be potential candidates for spintronic and modern microelectronic devices.