Research in nanotechnology involves the development of new materials at the nanometric scale, especially in the case of nanoparticles, where the use of metals and semiconductors has been the object of intense research. In this work, we have reported the synthesis of novel nanomaterials based on bimetallic particles of rare earths, which opens a new field of application for lanthanides in nanophotonics, nanoelectronics, and nanomedicine. We report the synthesis of Eu-Au nanoparticles by bioreduction methods and the corresponding structural characterization by using high-resolution electron microscopy. Eu-Au nanoparticles were synthesized at different pH values, and all the nanoparticles were studied for their characteristics. Among the nanoparticles obtained at different pH values, pH = 8 was found to be optimal for obtaining the smallest clusters on the basis of the size distribution and other characteristics. The structures of these bimetallic clusters are comparable to the main metal clusters, which were reported earlier.