Uniform perpendicular and parallel staggered susceptibility of antiferromagnetic films

We investigate the thermodynamic behavior of antiferromagnetic films in external magnetic fields oriented perpendicular to the staggered magnetization. Within the systematic effective Lagrangian framework we first calculate the two-point function and the dispersion relation for the two types of magnons up to one-loop order. This allows us to split the two-loop free energy density into a piece that originates from noninteracting dressed magnons, and a second piece that corresponds to the genuine magnon–magnon interaction. We then discuss the low-temperature series for various thermodynamic quantities, including the parallel staggered and uniform perpendicular susceptibilities, and analyze the role of the spin–wave interaction at finite temperature. •Systematic thermodynamic analysis of antiferromagnetic films in mutually orthogonal magnetic and staggered fields.•Analysis of the impact of the spin–wave interaction in thermodynamic quantities of antiferromagnetic films.•Two-point function and dispersion relation of magnons in antiferromagnetic films.