Magnetic susceptibilities in a family of S=1/2 Kagome antiferromagnet

Details Magnetic susceptibilities in a family of S=1/2 Kagome antiferromagnet Magnetic susceptibilities in a family of S=1/2 Kagome antiferromagnet

2009-01-19

arxiv.org/abs/0901.2791v3

Physics

Condensed Matter

Strongly Correlated Electrons

12 pages, 9 figures. Submitted to Physical Review B. Errors on Fig. 7 were corrected

Scientific paper

Hexagonal antiferromagnets Cs$_2$Cu$_3$MF$_{12}$ (M = Zr, Hf and Sn) have uniform Kagome lattices of Cu$^{2+}$ with S = 1/2, whereas Rb$_2$Cu$_3$SnF$_{12}$ has a 2a by 2a enlarged cell as compared with the uniform Kagome lattice. The crystal data of Cs$_2$Cu$_3$SnF$_{12}$ synthesized first in the present work are reported. We performed magnetic susceptibility measurements on this family of Kagome antiferromagnet using single crystals. In the Cs$_2$Cu$_3$MF$_{12}$ systems, structural phase transitions were observed at $T_t = 225$ K, 172 K and 185 K for M = Zr, Hf and Sn, respectively. The magnetic susceptibilities observed for $T > T_t$ are almost perfectly described using theoretical results obtained by exact diagonalization for the 24-site Kagome cluster with $J/k_B = 244$ K, 266 K and 240 K, respectively. Magnetic ordering accompanied by the weak ferromagnetic moment occurs at $T_N = 23.5$ K, 24.5 K and 20.0 K, respectively. The origins of the weak ferromagnetic moment should be ascribed to the lattice distortion that breaks the hexagonal symmetry of the exchange network for $T < T_t$ and the Dzyaloshinsky-Moriya interaction. Rb$_2$Cu$_3$SnF$_{12}$ is magnetically described as a modified Kagome antiferromagnet with four types of neighboring exchange interaction. Neither structural nor magnetic phase transition was observed in Rb$_2$Cu$_3$SnF$_{12}$. Its magnetic ground state was found to be a spin singlet with a triplet gap. Using exact diagonalization for a 12-site Kagome cluster, we analyzed the magnetic susceptibility and evaluated individual exchange interactions. The causes leading to the different ground states in Cs$_2$Cu$_3$SnF$_{12}$ and Rb$_2$Cu$_3$SnF$_{12}$ are discussed.

Affiliated with

Also associated with

No associations

Rating

Magnetic susceptibilities in a family of S=1/2 Kagome antiferromagnet does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Magnetic susceptibilities in a family of S=1/2 Kagome antiferromagnet, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnetic susceptibilities in a family of S=1/2 Kagome antiferromagnet will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-566492