中国物理B ›› 2023, Vol. 32 ›› Issue (5): 57506-057506.doi: 10.1088/1674-1056/acc2b3

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Spin reorientation in easy-plane kagome ferromagnet Li9Cr3(P2O7)3(PO4)2

Yuanhao Dong(董元浩)1, Ying Fu(付盈)2, Yixuan Liu(刘以轩)3, Zhanyang Hao(郝占阳)3, Le Wang(王乐)1, Cai Liu(刘才)1, Ke Deng(邓可)1, and Jiawei Mei(梅佳伟)1,4,†   

  1. 1 Shenzhen Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China;
    2 School of Physics, Xi'an Jiaotong University, Xi'an 710049, China;
    3 Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China;
    4 Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen 518055, China
  • 收稿日期:2022-12-08 修回日期:2023-02-21 接受日期:2023-03-09 出版日期:2023-04-21 发布日期:2023-04-21
  • 通讯作者: Jiawei Mei E-mail:meijw@sustech.edu.cn
  • 基金资助:
    Project supported by Shenzhen Fundamental Research Program (Grant No. JCYJ20220818100405013).

Spin reorientation in easy-plane kagome ferromagnet Li9Cr3(P2O7)3(PO4)2

Yuanhao Dong(董元浩)1, Ying Fu(付盈)2, Yixuan Liu(刘以轩)3, Zhanyang Hao(郝占阳)3, Le Wang(王乐)1, Cai Liu(刘才)1, Ke Deng(邓可)1, and Jiawei Mei(梅佳伟)1,4,†   

  1. 1 Shenzhen Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China;
    2 School of Physics, Xi'an Jiaotong University, Xi'an 710049, China;
    3 Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China;
    4 Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen 518055, China
  • Received:2022-12-08 Revised:2023-02-21 Accepted:2023-03-09 Online:2023-04-21 Published:2023-04-21
  • Contact: Jiawei Mei E-mail:meijw@sustech.edu.cn
  • Supported by:
    Project supported by Shenzhen Fundamental Research Program (Grant No. JCYJ20220818100405013).

摘要: We report the successful growth and characterization of Li$_9$Cr$_3$(P$_2$O$_7$)$_3$(PO$_4$)$_2$ single crystal, and investigate its magnetic properties under external magnetic fields via magnetization and heat capacity measurements. Our study reveals that Li$_9$Cr$_3$(P$_2$O$_7$)$_3$(PO$_4$)$_2$ is an easy-plane kagome ferromagnet with $S=3/2$, as evidenced by the Curie-Weiss temperature of 6 K which implies a ferromagnetic exchange coupling in the material. Under zero magnetic field, Li$_9$Cr$_3$(P$_2$O$_7$)$_3$(PO$_4$)$_2$ undergoes a magnetic transition at $T_{\rm C} = 2.7$ K from a paramagnetic state to a ferromagnetically ordered state with the magnetic moment lying in the kagome plane. By applying a $c$-axis directional magnetic field to rotate the spin alignment from the kagome plane to the $c$-axis, we observe a reduction in the magnetic transition temperature as the field is increased. We construct a magnetic phase diagram as a function of temperature and magnetic field applied parallel to the $c$-axis of Li$_9$Cr$_3$(P$_2$O$_7$)$_3$(PO$_4$)$_2$ and find that the phase boundary is linear over a certain temperature range. Regarding that theoretically, the field-induced phase transition of the spin reorientation in the easy-plane ferromagnet can be viewed as the ferromagnetic magnon Bose-Einstein condensation (BEC), the phase boundary scaling of field-induced ($B \parallel c$) magnetic transition in Li$_9$Cr$_3$(P$_2$O$_7$)$_3$(PO$_4$)$_2$ can be described as the quasi-2D magnon BEC, which has been observed in other ferromagnetic materials such as K$_2$CuF$_4$.

关键词: kagome lattice, flux method, magnetic material, spin-3/2

Abstract: We report the successful growth and characterization of Li$_9$Cr$_3$(P$_2$O$_7$)$_3$(PO$_4$)$_2$ single crystal, and investigate its magnetic properties under external magnetic fields via magnetization and heat capacity measurements. Our study reveals that Li$_9$Cr$_3$(P$_2$O$_7$)$_3$(PO$_4$)$_2$ is an easy-plane kagome ferromagnet with $S=3/2$, as evidenced by the Curie-Weiss temperature of 6 K which implies a ferromagnetic exchange coupling in the material. Under zero magnetic field, Li$_9$Cr$_3$(P$_2$O$_7$)$_3$(PO$_4$)$_2$ undergoes a magnetic transition at $T_{\rm C} = 2.7$ K from a paramagnetic state to a ferromagnetically ordered state with the magnetic moment lying in the kagome plane. By applying a $c$-axis directional magnetic field to rotate the spin alignment from the kagome plane to the $c$-axis, we observe a reduction in the magnetic transition temperature as the field is increased. We construct a magnetic phase diagram as a function of temperature and magnetic field applied parallel to the $c$-axis of Li$_9$Cr$_3$(P$_2$O$_7$)$_3$(PO$_4$)$_2$ and find that the phase boundary is linear over a certain temperature range. Regarding that theoretically, the field-induced phase transition of the spin reorientation in the easy-plane ferromagnet can be viewed as the ferromagnetic magnon Bose-Einstein condensation (BEC), the phase boundary scaling of field-induced ($B \parallel c$) magnetic transition in Li$_9$Cr$_3$(P$_2$O$_7$)$_3$(PO$_4$)$_2$ can be described as the quasi-2D magnon BEC, which has been observed in other ferromagnetic materials such as K$_2$CuF$_4$.

Key words: kagome lattice, flux method, magnetic material, spin-3/2

中图分类号:  (Static properties (order parameter, static susceptibility, heat capacities, critical exponents, etc.))

  • 75.40.Cx
06.60.Ei (Sample preparation) 61.05.cp (X-ray diffraction) 67.85.Jk (Other Bose-Einstein condensation phenomena)