Saturation Field of Frustrated Chain Cuprates: Broad Regions of Predominant Interchain Coupling

S. Nishimoto,
S.-L. Drechsler,
J. van den Brink,
J. Richter,
W. E. A. Lorenz,
Y. Skourski,
R. Klingeler,
B. Büchner

I. M. Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Krzhizhanovsky str., 3, Kyiv, 03142, Ukraine
Phys. Rev. Lett. - Maryland, USA: American Physical Society (APS), 2011, #107


A thermodynamic method to extract the interchain coupling (IC) of spatially anisotropic 2D or 3D spin-1/2 systems from their empirical saturation field Hs (T=0) is proposed. Using modern theoretical methods we study how Hs is affected by an antiferromagnetic (AFM) IC between frustrated chains described in the J1-J2-spin model with ferromagnetic 1st and AFM 2nd neighbor in-chain exchange. A complex 3D-phase diagram has been found. For Li2CuO2 and Ca2Y2Cu5O10, we show that Hs is solely determined by the IC and predict Hs≈61 T for the latter. With Hs≈55 T from magnetization data one reads out a weak IC for Li2CuO2 close to that obtained from inelastic neutron scattering.