Magnetic and Transport Studies in La$_x$Gd$_{1-x}$Rh$_3$B$_2$ and Ce$_x$Gd$_{1-x}$Rh$_3$B$_2$

The nonmagnetic rare earth ternary boride LaRh$_3$B$_2$, a hexagonal system of space group P6/mmm with CeCo$_3$B$_2$ type structure, is known to superconduct below T$_c$(0)$\sim$ 2.7 K. When doped with Gd the T$_c$(0) reduces and no superconductivity is observed above 1.2 K with more than 15\% (atomic) doping. The alloys, La$_{0.8}$Gd$_{0.2}$Rh$_3$B$_2$ and La$_{0.6}$Gd$_{0.4}$Rh$_3$B$_2$ show a jump at $\sim$ 70 K and rapid rise in magnetization below 10 K. However, no peaks are observed in at these temperatures in AC susceptibility which would have indicated magnetic ordering of the system. It is worth noting that GdRh$_3$B$_2$ orders ferromagnetically at $\sim $ 93 K. We shall present results of our investigations, above 2 K, in magnetic and transport properties of polycrystalline specimens La$_x$Gd$_{1-x}$Rh$_3$B$_2$ (0 $<$ x $ <$ 1). CeRh$_3$B$_2$ is a ferromagnet with T$_c$ $\sim$ 115 K. The results of Gd doping in this reveal the survival of antiferromagnetic coupling between Ce and Gd spins.