AI 中文总结
本研究设计了一种可在20-300 K、最高7.5 kOe磁场下工作的定制闭循环制冷机装置，用于动态锁相磁电耦合测量，经CFO-BTO复合体系验证，可用于探究多铁复合材料和量子材料的弱磁电耦合及相变。
AI 中文摘要
新兴材料体系中的磁电（ME）现象，如二维范德华（vdW）磁体和单分子磁体（SMMs），对下一代低温存储器和量子技术具有巨大应用前景。然而，这些体系中的磁电耦合主要在低温下显现，因此开发灵敏且兼容低温环境的磁电表征技术至关重要。为满足这一需求，我们报告了一种定制的闭循环制冷机装置的设计、验证及性能，该装置可在20-300 K温度范围、最高7.5 kOe的直流磁场下实现动态锁相磁电耦合测量，同时给出了抑制寄生感应背景信号的关键设计考量。我们利用钴铁氧体-钛酸钡（CFO-BTO）颗粒复合体系对该装置进行验证，成功复现了室温下典型的蝶形磁电回线，在约3 kOe磁场下测得最大磁电系数为0.23 mV/cm-Oe。变温测量在约200 K和280 K处分辨出磁电异常，与钛酸钡的菱方-正交、正交-四方结构转变重合，且无需重新配置制冷机即可对同一样品同步进行介电测量，验证了该结果。该装置可在低至20 K的温度下实现可靠的磁电与介电表征，非常适合探究多铁复合材料和量子材料中的弱磁电耦合及相变。
英文摘要
Magnetoelectric (ME) phenomena in emerging material classes, such as two-dimensional van der Waals (vdW) magnets and Single-Molecule Magnets (SMMs), hold immense promise for next-generation cryogenic memory and quantum technologies. However, ME coupling in these systems predominantly manifests at low temperatures, making a sensitive, cryo-compatible ME characterization techniques critical. To address this requirement, we report the design, validation, and performance of a custom closed-cycle refrigerator-based setup for dynamic lock-in ME coupling measurements across 20-300 K under dc magnetic fields up to 7.5 kOe. Key design considerations for mitigating parasitic inductive background signals are also presented. The setup was validated on a CoFe2O4-BaTiO3 (CFO-BTO) particulate composite, reproducing the characteristic room-temperature butterfly ME loop with a maximum ME coefficient value of 0.23 mV/cm-Oe at ~ 3 kOe. Temperature-dependent measurements resolved ME anomalies at ~ 200 K and 280 K, coinciding with the rhombohedral-orthorhombic and orthorhombic-tetragonal structural transitions of BaTiO3, and were corroborated by simultaneous dielectric measurements on the same sample without cryostat reconfiguration. The instrument enables reliable ME and dielectric characterization down to 20 K, making it well suited for probing weak magnetoelectric coupling and phase transitions in multiferroic composites and quantum materials.
