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arXiv · 1107.0250

Magnetic model for A2CuP2O7 (A = Na, Li) revisited: 1D versus 2D behavior

S. Lebernegg·A. A. Tsirlin·O. Janson·R. Nath·Yu. Skourski·G. Amthauer·H. Rosner
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Abstract

We report magnetization measurements, full-potential band structure calculations, and microscopic modeling for the spin-1/2 Heisenberg magnets A2CuP2O7 (A = Na, Li). Based on a quantitative evaluation of the leading exchange integrals and the subsequent quantum Monte-Carlo simulations, we propose a quasi-one-dimensional magnetic model for both compounds, in contrast to earlier studies that conjectured on the two-dimensional scenario. The one-dimensional nature of A2CuP2O7 is unambiguously verified by magnetization isotherms measured in fields up to 50 T. The saturation fields of about 40 T for both Li and Na compounds are in excellent agreement with the intrachain exchange J1 ~ 27 K extracted from the magnetic susceptibility data. The proposed magnetic structure entails spin chains with the dominating antiferromagnetic nearest-neighbor interaction J1 and two inequivalent, nonfrustrated antiferromagnetic interchain couplings of about 0.01*J1 each. A possible long-range magnetic ordering is discussed in comparison with the available experimental information.

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S. Lebernegg, A. A. Tsirlin, O. Janson, R. Nath, Yu. Skourski, G. Amthauer, H. Rosner. 2011-07-01. Magnetic model for A2CuP2O7 (A = Na, Li) revisited: 1D versus 2D behavior. https://doi.org/10.1103/physrevb.84.174436

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