Geometrically frustrated kagome-lattice antiferromagnets have received much attention because of their exotic magnetic behaviors. Here we report the synthesis, structure, and magnetism of an S=5/2 quasiclassical new spin kagome compound. Polycrystalline compounds of MgxMn4-x(OH)6Cl2, with a nominal ideal chemical formula of MgMn3(OH)6Cl2, have been successfully synthesized by selectively substituting the triangular-lattice-plane Mn2+ with nonmagnetic Mg2+. The compounds studied crystallize in rhombohedral structure in space group R-3m, in a similar crystal structure to the much-researched quantum spin liquid candidates herbertsmithite ZnCu3(OH)6Cl2 and tondiite MgCu3(OH)6Cl2. Antiferromagnetic transition below TN∼8K and a 120° nearest-neighbor spin ordering confined in the kagome plane with positive spin chirality have been revealed by magnetic susceptibility measurements and neutron diffraction experiment. The obtained value of critical exponent β=0.35 agrees with a three-dimensional Heisenberg spin model. The present work suggests the intrinsic nature of long-range order in classical Heisenberg kagome aniferromagnet and provides a classical reference system to quantum kagome antiferromagnets.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics