High-field Phase Diagram and Spin Structure of Volborthite Cu3V2O7(OH)2/2H2O

Abstract

We report results of 51V NMR experiments on a high-quality powder sample of volborthite Cu3V2O7(OH)2/2H2O, a spin-1/2 Heisenberg antiferromagnet on a distorted kagome lattice. Following the previous experiments in magnetic fields $B$ below 12 T, the NMR measurements have been extended to higher fields up to 31 T. In addition to the two already known ordered phases (phases I and II), we found a new high-field phase (phase III) above 25 T, at which a second magnetization step has been observed. The transition from the paramagnetic phase to the antiferromagnetic phase III occurs at 26 K, which is much higher than the transition temperatures from the paramagnetic to the lower field phases I (B < 4.5 T) and II (4.5 < B < 25 T). At low temperatures, two types of the V sites are observed with different relaxation rates and line shapes in phase III as well as in phase II. Our results indicate that both phases II and III exhibit a heterogeneous spin state consisting of two spatially alternating Cu spin systems, one of which exhibits anomalous spin fluctuations contrasting with the other showing a conventional static order. The magnetization of the latter system exhibits a sudden increase upon entering into phase III, resulting in the second magnetization step at 26 T.We discuss the possible spin structure in phase III.

9 pages, 12 figures

References in corpus (16)

• Spin Dynamics of the Spin-1/2 Kagome Lattice Antiferromagnet ZnCu_3(OH)_6Cl_2
• Properties of an algebraic spin liquid on the kagome lattice
• 17O NMR study of the intrinsic magnetic susceptibility and spin dynamics of the quantum kagome antiferromagnet ZnCu3(OH)6Cl2
• Ground State of the Kagome Lattice Heisenberg Antiferromagnet
• Vesignieite BaCu3V2O8(OH)2 as a Candidate Spin-1/2 Kagome Antiferromagnet
• Quantum phase transition induced by Dzyaloshinskii-Moriya in the kagome antiferromagnet
• ^{63}Cu, ^{35}Cl, and ^{1}H NMR in the S=1/2 Kagomé Lattice ZnCu_{3}(OH)_{6}Cl_{2}
• Twelve sublattice ordered phase in the J1-J2 model on the kagome lattice
• Magnetization Plateaus in the Spin-1/2 Kagome Antiferromagnets: Volborthite and Vesignieite
• Magnetization Process of Kagome-Lattice Heisenberg Antiferromagnet
• Spatially Anisotropic Heisenberg Kagome Antiferromagnet
• Singlet Ground State and Spin Gap in S=1/2 Kagome Antiferromagnet Rb${}_2$Cu${}_3$SnF${}_{12}$
• Quantum and Classical Spins on the Spatially Distorted Kagome Lattice: Applications to Volborthite
• Coupled frustrated quantum spin-1/2 chains with orbital order in volborthite Cu3V2O7(OH)2(H2O)2
• Heterogeneous spin state in the field-induced phase of volborthite as seen via 51V nuclear magnetic resonance
• Ordered Phases of the Anisotropic Kagome Lattice Antiferromagnet in a Field

Cited by in corpus (9)

• Emergence of nontrivial magnetic excitations in a spin liquid state of kagome volborthite
• One-Third Magnetization Plateau with a Preceding Novel Phase in Volborthite
• Quantum Magnetism in Minerals
• The spin gap in malachite Cu2(OH)2CO3 and its evolution under pressure
• Magnetic Order in the Spin-1/2 Kagome Antiferromagnet Vesignieite
• Spin dynamics in the high-field phases of volborthite
• Topological Magnetic Excitations on the Distorted Kagome Antiferromagnets: Applications to Volborthite, Vesignieite, and Edwardsite
• Magnon Hall Effect without Dzyaloshinskii-Moriya Interaction
• Effects of Dzyaloshinskii-Moriya interactions in volborthite: Magnetic orders and thermal Hall effect