Magnetic structure and dzyaloshinskii-moriya interaction in the S=12 helical-honeycomb antiferromagnet α−Cu2V2O7
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Date
2015-07-23
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Publisher
American Physical Society
Abstract
Magnetic properties of the S=12 antiferromagnet α−Cu2V2O7 have been studied using magnetization, quantum Monte Carlo (QMC) simulations, and neutron diffraction. Magnetic susceptibility shows a broad peak at ∼50K followed by an abrupt increase indicative of a phase transition to a magnetically ordered state at TN=33.4(1) K. Above TN, a fit to the Curie-Weiss law gives a Curie-Weiss temperature of Θ=−73(1) K suggesting the dominant antiferromagnetic coupling. The result of the QMC calculations on the helical-honeycomb spin network with two antiferromagnetic exchange interactions J1 and J2 provides a better fit to the susceptibility than the previously proposed spin-chain model. Two sets of the coupling parameters J1:J2=1:0.45 with J1=5.79(1) meV and 0.65:1 with J2=6.31(1) meV yield equally good fits down to ∼TN. Below TN, weak ferromagnetism due to spin canting is observed. The canting is caused by the Dzyaloshinskii-Moriya interaction with an estimated bc-plane component |Dp|≃0.14J1. Neutron diffraction reveals that the S=12Cu2+ spins antiferromagnetically align in the Fd′d′2 magnetic space group. The ordered moment of 0.93(9) μB is predominantly along the crystallographic a axis. ©2015 American Physical Society
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Keywords
Magnetic properties, Antiferromagnetism, Neutron diffraction, Monte Carlo Method, Phase transformations, Spin
Citation
Gitgeatpong, G., Zhao, Y., Avdeev, M., Piltz, R. O., Sato, T. J., & Matan, K. (2015) Magnetic structure and dzyaloshinskii-moriya interaction in the S=12 helical-honeycomb antiferromagnet α−Cu2V2O7. Physical Review B, 92(2), 024423. doi:10.1103/PhysRevB.92.024423