GdPtPb: A non collinear antiferromagnet with distorted Kagom\'e lattice

In the spirit of searching for Gd-based, frustrated, rare earth magnets, we have found antiferomagnetism (AF) in GdPtPb which crystallizes in the ZrNiAl-type structure that has a distorted Kagom\'e lattice of Gd-triangles. Single crystals were grown and investigated using structural, magnetic, transport and thermodynamic measurements. GdPtPb orders antiferromagnetically at 15.5 K arguably with a planar, non-collinear structure. The high temperature magnetic susceptibility data reveal an "anti-frustration" behavior having a frustration parameter, $|f|$ = $|\Theta|$/ $T_N$ = 0.25, which can be explained by mean field theory (MFT) within a two sub-lattice model. Study of the magnetic phase diagram down to $T$ = 1.8 K reveals a change of magnetic structure through a metamagnetic transition at around 20 kOe and the disappearance of the AF ordering near 140 kOe. In total, our work indicates that, GdPtPb can serve as an example of a planar, non collinear, AF with a distorted Kagom\'e magnetic sub-lattice.