Evidence of a Low Energy Anisotropy in GdCoIn\(_5\)

We investigate the effects of an applied magnetic field on the magnetic properties of the antiferromagnet GdCoIn\(_5\). The prominent anisotropy observed in the susceptibility below \(T_N\) is rapidly suppressed by a field of just a few Tesla. Further evidence of this low energy-scale is obtained from magnetoresistance and magnetostriction experiments. The lattice length, particularly, shows a sudden change below 2 T when the magnetic field is applied perpendicular to the crystallographic \(\hat{c}\)-axis.