Ding Jie, Zhu Xinhua
National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, People's Republic of China.
J Phys Condens Matter. 2025 Jan 22;37(11). doi: 10.1088/1361-648X/ada50b.
Driven by the miniaturization of microelectronic devices and their multifunctionalities, the development of new quadruple-perovskite oxides with high dielectric constants and high Curie temperature are highly required. Herein, we report on the structural, dielectric and magnetic properties of Sb/Cr-doped CaCuTiO(CCTO) quadruple perovskite oxides, CaCuTiSbO(CCTSO) and CaCuTiCrO(CCTCO). Structural Rietveld refinements demonstrated that the CCTO, CCTSO, and CCTCO ceramics adopted a cubic crystal structure (3¯ space group). They exhibited spherical shapes with nearly uniform particle sizes. XPS spectra clarified Cuions in the CCTSO ceramics, while Cuand Cuions, and Crions in the CCTCO ceramics. All the ceramic samples displayed nearly frequency independent dielectric behaviors at low temperatures but a relaxor dielectric behavior at high temperatures. Such relaxor dielectric behavior in the CCTO and CCTSO ceramics was ascribed to the movement of doubly ionized oxygen vacancies but in the CCTCO ceramics to the movement of singly ionized oxygen vacancies. Impedance and modulus spectra reveal the significance contributions of grains and grain boundaries with non-Debye behavior. At room temperature (RT) the dielectric constant () and dielectric loss (tan) of CCTO ceramics at 1 kHz were 15 922 and 0.126, respectively. An order reduction of tanwas achieved in the CCTSO ceramics. In the CCTCO ceramics, theand tanat RT and 1 kHz were 975 and 0.453, respectively. The CCTCO powders exhibited antiferroelectric behavior at 2 K with a saturation magnetization () of 1.42/f.u., while thefor the CCTSO powders was only 0.027/f.u. All ceramic samples exhibited semiconductor characteristics owing to their continuous decreases of resistivity from 2 K to 800 K. Our present work demonstrates an effective route to tuning the dielectric and magnetic properties of CCTO oxides via B-site non-magnetic/magnetic ion-doping.
受微电子器件小型化及其多功能性的驱动，对具有高介电常数和高居里温度的新型四重钙钛矿氧化物的开发需求迫切。在此，我们报道了Sb/Cr掺杂的CaCuTiO（CCTO）四重钙钛矿氧化物CaCuTiSbO（CCTSO）和CaCuTiCrO（CCTCO）的结构、介电和磁性。结构Rietveld精修表明，CCTO、CCTSO和CCTCO陶瓷采用立方晶体结构（3¯ 空间群）。它们呈现出球形，粒径几乎均匀。XPS光谱明确了CCTSO陶瓷中的Cu离子，而CCTCO陶瓷中的Cu²⁺和Cu⁺离子以及Cr³⁺离子。所有陶瓷样品在低温下表现出几乎与频率无关的介电行为，但在高温下表现出弛豫铁电体介电行为。CCTO和CCTSO陶瓷中的这种弛豫铁电体介电行为归因于双电离氧空位的移动，而CCTCO陶瓷中的归因于单电离氧空位的移动。阻抗和模量谱揭示了具有非德拜行为的晶粒和晶界的重要贡献。在室温（RT）下，CCTO陶瓷在1 kHz时的介电常数（ε）和介电损耗（tanδ）分别为15922和0.126。CCTSO陶瓷的tanδ实现了一个数量级的降低。在CCTCO陶瓷中，RT和1 kHz时的ε和tanδ分别为975和0.453。CCTCO粉末在2 K时表现出反铁电行为，饱和磁化强度（Ms）为1.42/f.u.，而CCTSO粉末的Ms仅为0.027/f.u.。所有陶瓷样品由于其电阻率从2 K到800 K持续降低而表现出半导体特性。我们目前的工作展示了一种通过B位非磁性/磁性离子掺杂来调节CCTO氧化物介电和磁性的有效途径。
