We report the magnetic phase transitions of a spin-5/2, 2-dimensional triangular lattice antiferromagnet (AFM) Na2BaMn(PO4)2. From specific heat measurements, we observe two magnetic transitions at temperatures 1.15 and 1.30 K at zero magnetic field. Detailed AC magnetic susceptibility measurements reveal multiple phases including the ↑↑↓ (up-up-down)-phase between 1.9 and 2.9 T at 47 mK when magnetic field is applied along the c axis, implying that Na2BaMn(PO4)2 is a classical 2d TL Heisenberg AFM with easy-axis anisotropy. However, it deviates from an ideal model as evidenced by a hump region with hysteresis between the ↑↑↓ and V-phases and weak phase transitions. Our work provides another experimental example to study frustrated magnetism in 2d TL AFM which also serves as a reference to understand the possible quantum spin liquid behavior and anomalous phase diagrams observed in sibling systems Na2BaM(PO4)2 (M = Co, Ni).
Bibliographical noteFunding Information:
We thank T H Jang at MPK-POSTECH for carrying out the C measurement in DR. J K acknowledges Sungdae Ji, Bongjae Kim, Ara Go, Heung-Sik Kim and Jiyeon Kim for helpful discussions and M Kim for critical reading of the manuscript. This work is supported by the KAERI Internal R&D program (Grant Nos. 524460-22 and 79772-21) and National Research Foundation of Korea (No. 2021M2E3A3040092). The National High Magnetic Field Laboratory is supported by the National Science Foundation through NSF/DMR-1644779 and the State of Florida. p
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- magnetic phase diagram
- triangular lattice antiferromagnet
ASJC Scopus subject areas
- General Materials Science
- Condensed Matter Physics