Hexagonal RMnO3 (R = Er, Ho and Yb) single crystals were grown and their unique vortex domain structures, magnetic properties and magnetocaloric effect (MCE) were comprehensively investigated. The topological vortex domains/structures were clearly illustrated by polarized optical microscope and piezo response force microscopy, confirming a high quality of the crystals. The magnetic transitions related to R3+-Mn3+ interactions and anisotropic properties were observed in the RMnO3 crystals. The broad peaks of magnetic entropy change -SM appeared around T_N^R revealed that the order of R3+ moments is crucial to the large MCE. A giant rotating MCE (RMCE: ~10.57 J/kg K) was obtained with magnetic field changing from 0 to 50 kOe in ErMnO3, accompanied with a large refrigerant capacity (RC: ~159 J/kg). These significant RMCE and RC behaviors are found to be closely related to the R3+-R3+, and R3+-Mn3+ interactions in these RMnO3. These results may open up a possibility for designing low-temperature magnetic cooling devices by tailoring the R-4f and Mn-3d orbit interactions.

中文翻译：

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观察到的拓扑涡流域和六方 RMnO3（R = Ho、Er 和 Yb）晶体中的旋转磁热效应

生长了六方 RMnO3 (R = Er、Ho 和 Yb) 单晶，并对其独特的涡畴结构、磁性和磁热效应 (MCE) 进行了全面研究。偏光光学显微镜和压电响应力显微镜清楚地说明了拓扑涡旋域/结构，证实了晶体的高质量。在 RMnO3 晶体中观察到与 R3+-Mn3+ 相互作用和各向异性特性相关的磁跃迁。磁熵变的宽峰-SM 出现在 T_N^R 附近，表明 R3+ 矩的阶数对大 MCE 至关重要。在 ErMnO3 中磁场从 0 到 50 kOe 变化时获得了一个巨大的旋转 MCE（RMCE：~10.57 J/kg K），伴随着大制冷剂容量（RC：~159 J/kg）。发现这些显着的 RMCE 和 RC 行为与这些 RMnO3 中的 R3+-R3+ 和 R3+-Mn3+ 相互作用密切相关。这些结果可能为通过调整 R-4f 和 Mn-3d 轨道相互作用来设计低温磁冷却装置开辟了可能性。