1210.4414 (M. Härtel et al.)

Thermodynamics of the two-dimensional frustrated J1-J2 Heisenberg
ferromagnet in the collinear stripe regime: Susceptibility and correlation
length    [PDF]

M. Härtel, J. Richter, O. Götze, D. Ihle, S. -L. Drechsler

We calculate the temperature dependence of the correlation length xi and the uniform susceptibility chi_0 of the frustrated J1-J2 square-lattice Heisenberg ferromagnet in the collinear stripe phase using Green-function technique. The height chi_{max} and the position T(chi_{max}) of the maximum in the chi_0(T) curve exhibit a characteristic dependence on the frustration parameter J2/|J1|, which is well described by power laws, chi_{max}=a(J2-J2^c)^{-nu} and T(chi_{max})=b(J_2-J_2^c), where J2^c = 0.4 and nu is of the order of unity.The correlation length diverges at low temperatures as xi \propto e^{A/T}, where A increases with growing J2/|J1|. We also compare our results with recent measurements on layered vanadium phosphates and find reasonable agreement.

View original: http://arxiv.org/abs/1210.4414