Collective and local excitations in Ba2CoTeO6 : A composite system of a spin-1/2 triangular-lattice Heisenberg antiferromagnet and a honeycomb-lattice J1−J2 Ising antiferromagnet
| Autor: | Hiroyuki Nojiri, Nobuyuki Kurita, Motoi Kimata, Hidekazu Tanaka, Purintorn Chanlert |
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| Rok vydání: | 2017 |
| Předmět: |
Physics
Condensed matter physics 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Magnetic field Magnetization Lattice (order) 0103 physical sciences Antiferromagnetism Condensed Matter::Strongly Correlated Electrons Hexagonal lattice Ising model 010306 general physics 0210 nano-technology Anisotropy Excitation |
| Zdroj: | Physical Review B. 96 |
| ISSN: | 2469-9969 2469-9950 |
| DOI: | 10.1103/physrevb.96.064419 |
| Popis: | We report the results of multifrequency high-magnetic-field electron-spin resonance (ESR) measurements on the highly frustrated antiferromagnet ${\mathrm{Ba}}_{2}{\mathrm{CoTeO}}_{6}$. This compound is magnetically composed of two subsystems A and B, which are described as a spin-1/2 triangular-lattice Heisenberg antiferromagnet and a honeycomb-lattice ${J}_{1}\ensuremath{-}{J}_{2}$ Ising antiferromagnet, respectively. ${\mathrm{Ba}}_{2}{\mathrm{CoTeO}}_{6}$ undergoes successive magnetic phase transitions at ${T}_{\mathrm{N}1}\phantom{\rule{0.16em}{0ex}}=\phantom{\rule{0.16em}{0ex}}12.0$ K and ${T}_{\mathrm{N}2}\phantom{\rule{0.16em}{0ex}}=\phantom{\rule{0.16em}{0ex}}3.0$ K. For a magnetic field $H$ parallel to the $c$ axis, subsystem B exhibits successive metamagnetic transitions with magnetization plateaus at one-third and one-half of the saturation magnetization. Below ${T}_{\mathrm{N}2}$, we observed collective ESR modes for $H\phantom{\rule{0.16em}{0ex}}\ensuremath{\parallel}\phantom{\rule{0.16em}{0ex}}c$, which are characteristic of a triangular-lattice Heisenberg antiferromagnet with weak easy-plane anisotropy. We also observed a local excitation mode, which can be assigned as a single flip of the Ising-like spin of subsystem B. From a detailed analysis of the collective and local ESR modes, combined with the magnetization process, we determined the magnetic parameters of subsystems A and B, and confirmed that the two subsystems are almost decoupled. |
| Databáze: | OpenAIRE |
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