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

TL;DR

This study investigates the temperature-dependent magnetic properties of a frustrated 2D J1-J2 Heisenberg ferromagnet in the collinear stripe phase, revealing characteristic power-law behaviors and divergence of correlation length, with implications for layered vanadium phosphates.

Contribution

It provides a detailed analysis of susceptibility and correlation length in the frustrated J1-J2 model using Green-function techniques, highlighting new power-law dependencies and divergence behavior.

Findings

Susceptibility maximum scales as a power law with frustration parameter.

Correlation length diverges exponentially at low temperatures.

Results agree reasonably with experimental data on layered vanadium phosphates.

Abstract

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.