Synthesis and characterization of single crystal kagomé lattice antiferromagnets

Abstract

An ideal spin-% kagomé lattice has been a long sought material. This system is characterized by strong magnetic frustration and is a likely candidate for a spin-liquid ground state. The spin-liquid state was originally proposed to exist in the parent compounds of the high temperature superconducting cuprates as originally proposed by Anderson. However, the lack of ideal samples have hampered experimental tests of the theories. A few years ago, a kagomé lattice material called herbertsmithite (ZnCu3(OH)6Cl2) has been successfully synthesized and studied. Since then, many experiments have been performed which have produced a lot of new guidance for our theoretical understanding of this frustrated magnetic system. However, single crystals are crucial for further progress. We have successfully produced high quality single crystals ZnCu3(OH)6Cl2 . These crystals are large enough for measurements, such as x-ray diffraction, magnetism, heat capacity, neutron scattering, thermal conductivity, muon-scattering and optical measurement. In this thesis, I will summarize the current state of knowledge for herbertsmithite and its family, the single crystal growth technique, and characterization of the resulting samples. A discussion of further directions of growth and measurement is at the end.