Yang Wanting, Chen Haiyang, Peng Haohuan, Lin Zhaodi, Zheng Yubing, Ma Xiaoxuan, Jia Rongrong, Kang Baojuan, Feng Zhenjie, Cao Shixun
Department of Physics, Materials Genome Institute, Institute for Quantum Science and Technology, Shanghai University, Shanghai 200444, China.
Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
Phys Chem Chem Phys. 2024 Aug 7;26(31):20820-20827. doi: 10.1039/d4cp02000f.
Magnetic refrigeration based on the magnetocaloric effect is gaining interest in orthogonal or hexagonal rare-earth manganite. However, a more comprehensive understanding of the underlying mechanism is still required. We grew a high-quality single crystal of DyHoMnO using the optical floating zone method, since the parent crystals DyMnO and HoMnO have orthogonal and hexagonal structures, respectively. The magnetic and magnetocaloric properties and refrigeration mechanisms are thoroughly investigated. Doping modifies the magnetism according to the results obtained from the investigation of magnetic and dielectric properties and heat capacity. The spin reorientation transition shifts towards low temperature in comparison to HoMnO. Near the Néel temperature of rare-earth sublattices (5 K), the highest changes in negative magnetic entropy under 0-70 kOe are 18 J kg K and 13 J kg K along the - and -axes, respectively. The low-temperature metamagnetic phase transition caused by the alterations in the magnetic symmetry of Ho contributes to an increased magnetocaloric effect in comparison to the parent crystals, rendering it a promising choice for magnetic refrigeration applications. DyHoMnO exhibits a clear magnetocrystalline anisotropy with enhanced refrigeration capacity and negative magnetic entropy change along the -axis. The adiabatic temperature change of DyHoMnO is 8.5 K, larger than that of HoMnO, rendering it a promising choice for low-temperature magnetic refrigeration applications.
基于磁热效应的磁制冷在正交或六方稀土锰酸盐中越来越受到关注。然而，仍需要对其潜在机制有更全面的了解。我们使用光学浮区法生长了高质量的DyHoMnO单晶，因为母体晶体DyMnO和HoMnO分别具有正交和六方结构。对其磁性、磁热性质和制冷机制进行了深入研究。根据磁性、介电性质和热容量的研究结果，掺杂改变了磁性。与HoMnO相比，自旋重取向转变向低温方向移动。在稀土亚晶格的奈尔温度（5 K）附近，在0 - 70 kOe下，沿-轴和-轴的负磁熵最大变化分别为18 J kg K和13 J kg K。与母体晶体相比，由Ho的磁对称性变化引起的低温变磁性相变导致磁热效应增强，使其成为磁制冷应用的一个有前途的选择。DyHoMnO表现出明显的磁晶各向异性，沿-轴具有增强的制冷能力和负磁熵变化。DyHoMnO的绝热温度变化为8.5 K，大于HoMnO，使其成为低温磁制冷应用的一个有前途的选择。
