Exploring a New Family of S = ½ Kagomé Antiferromagnets
Speaker: Dr Lucy Clark, University of Birmingham
Title: Exploring a New Family of S = ½ Kagomé Antiferromagnets
Abstract: Materials constructed from kagomé layers of antiferromagnetically coupled S = ½ moments are highly prized as they offer a unique opportunity to explore elusive quantum spin liquid (QSL) states. Recently, the Cu2+-based mineral known as Zn-doped barlowite, ZnCu3(OH)6FBr, has shown promise as a new realisation of the QSL state. Despite this interest, the crystal and magnetic structures of the parent material barlowite, Cu4(OH)6FBr, are poorly understood with several conflicting reports in the literature.[3-5] In this seminar, I will introduce these developments in the field of highly frustrated magnetism before presenting our comprehensive neutron diffraction studies of barlowite. In doing so, I will discuss the intriguing structural phase transition we observe in this material at T = 250 K, and clarify the nature of the magnetic ground state below TN = 15 K. In addition, I will show that we can tune the magnetic ground state of barlowite from antiferromagnetic order to quantum disorder upon Zn-doping though muon spectroscopy measurements supported by density-functional theory.
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