Transition-metal distribution in kagome antiferromagnet CoCu3(OH)6Cl2 revealed by resonant x-ray diffraction

TL;DR

This study uses resonant x-ray diffraction to precisely determine the distribution of transition-metal ions in CoCu3(OH)6Cl2, revealing complex low-temperature magnetic behavior in a kagome antiferromagnet.

Contribution

It provides the first exact distribution of transition-metal ions in CoCu3(OH)6Cl2 using resonant x-ray diffraction, linking ion distribution to magnetic properties.

Findings

Transition-metal ions distribution was precisely determined.

Magnetic susceptibility and heat capacity align with ion distribution.

Low-temperature spin-glass freezing observed in interlayer spins.

Abstract

The distribution of chemically similar transition-metal ions is a fundamental issue in the study of herbertsmithite-type kagome antiferromagnets. Using synchrotron radiation, we have performed resonant powder x-ray diffractions on newly synthesized CoCu3(OH)6Cl2, which provide an exact distribution of transition-metal ions in the frustrated antiferromagnet. Both magnetic susceptibility and specific heat measurements are quantitatively consistent with the occupation fractions determined by resonant x-ray diffraction. The distribution of transition-metal ions and residual magnetic entropy suggest a novel low temperature (T < 4 K) magnetism, where the interlayer triangular spins undergo a spin-glass freezing while the kagome spins still keep highly frustrated.