Magnetic couplings in the quasi-2D triangular Heisenberg antiferromagnets α-ACr2O4 (A=Ca, Sr, Ba)

► Increasing the ionic radius of A2+ has a non-monotonous impact on TN. ► The small single-ion anisotropy can split the antiferromagnetic transition. ► The intraplane coupling is consistent with direct exchange. ► The interplane coupling derived from standard 2DTHAF models is questionable.