Magnetic Ground State and Magnetic Excitations in Black Dioptase Cu6Si6O18

Published

November 1, 2019

Author(s)

A. Podlesnyak, O. Prokhnenko, S. E. Nikitin, A. I. Kolesnikov, M. Matsuda, Sachith E. Dissanayake, Timothy R Prisk, H. Nojiri, I. F. Diaz-Ortega, L. M. Anovitz

Abstract

The low-temperature magnetic properties and magnetic structure of fully dehydrated black dioptase Cu₆Si₆O₁₈ have been studied by single-crystal neutron diffraction and magnetization measurements in magnetic fields up to 30 T. The intrachain J_c and interchain J_ab interactions as well as the anisotropy of the exchange coupling J_c have been determined using inelastic neutron scattering technique. Zero-field antiferromagnetic order at T_N = 6.7 K can be described by a commensurate propagation vector of K = (0,0,3/2) with respect to the hexagonal R3:H unit cell. The Cu magnetic moments are aligned antiferromagnetically along the c-axis with about 12° tilt and are coupled ferromagnetically between the chains. The high-field magnetization measurements provide strong evidence for the presence of a spin-flop phase above 8 T. We found that J_c in black dioptase is significantly increased, while J_ab is much weaker, compared to its counterpart, green dioptase Cu₆[Si₆O₁₈]&#82266H₂O. We suggest that black dioptase behaves like a nearly ideal spiral S=1/2 antiferromagnetic Heisenberg chain with enhanced quantum fluctuations and weak spinon confinement J_ab/J_c 0.02.

Citation

Physical Review B

Volume

100

Issue

18

Pub Type

Journals

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Citation

Podlesnyak, A. , Prokhnenko, O. , Nikitin, S. , Kolesnikov, A. , Matsuda, M. , Dissanayake, S. , Prisk, T. , Nojiri, H. , Diaz-Ortega, I. and Anovitz, L. (2019), Magnetic Ground State and Magnetic Excitations in Black Dioptase Cu₆Si₆O₁₈, Physical Review B, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=928219 (Accessed April 25, 2024)