Magnetic model forA2CuP2O7(A=Na, Li): One-dimensional versus two-dimensional behavior

S. Lebernegg, A. A. Tsirlin, O. Janson, R. Nath, J. Sichelschmidt, Yu. Skourski, G. Amthauer, H. Rosner
2011 Physical Review B  
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
more » ... ed 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.
doi:10.1103/physrevb.84.174436 fatcat:7daqfvxwknghzawu2vh6epv6my