Realization of an excellent two-dimensional Heisenberg ferromagnetic system: the synthesis, structure, and thermodynamic properties of piperazinediium tetrabromocuprate
| Autor: | Lichun Zhang, Hu Feng, Xiangmu Kong, Binglin Pan, Shiyan Li, Xiangnan Gong, Ming-Cui Ding, Jiaxi Qiu, Bingying Pan, Yuliang Xu |
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| Rok vydání: | 2019 |
| Předmět: |
Materials science
Condensed matter physics Spins Isotropy 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Magnetic susceptibility Inelastic neutron scattering 0104 chemical sciences law.invention Ferromagnetism law Materials Chemistry 0210 nano-technology Electron paramagnetic resonance Single crystal Realization (systems) |
| Zdroj: | Journal of Materials Chemistry C. 7:8813-8819 |
| ISSN: | 2050-7534 2050-7526 |
| DOI: | 10.1039/c9tc01878f |
| Popis: | As to the prototypical realization of the famous Mermin–Wagner theorem, two dimensional Heisenberg ferromagnets (2D HFMs) are expected to have no static order at finite temperatures [N. D. Mermin and H. Wagner, Phys. Rev. Lett., 1966, 17, 1133]. However, a perfect 2D HFM with negligible inter-layer exchange is still lacking, impeding studies of its novel properties. Here we report the synthesis, structure, and properties of a new metal–organic single crystal piperazinediium tetrabromocuprate ((C4H12N2)CuBr4, PTBC). The Cu2+ spins form perfect 2D layers which are well separated by organic ligands. Single crystal electron paramagnetic resonance (EPR) and magnetic susceptibility measurements reveal that PTBC is a highly isotropic Heisenberg ferromagnet with a strong intra-layer ferromagnetic exchange J/kB = 31.34(6) K (H‖ab) and 36.54(17) K (H⊥ab). However, it does not order down to 2 K, indicating the negligible inter-layer exchange J′ and ultra-small R ratio (R = J′/J) below 6 × 10−28. This is the smallest R ratio ever reported for a 2D HFM. These results imply that PTBC is by far the best realization of a 2D HFM system. Moreover, the typical single crystal size is as large as 20 mm × 20 mm × 3 mm, making it suitable for studying the magnetic dynamics of a 2D HFM by probes such as inelastic neutron scattering. |
| Databáze: | OpenAIRE |
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