Magnetic nanoparticles are currently being investigated comprehensively. Our ball-milled TbCu2 nanoparticles show a core-shell structure in which the core orders antiferromagnetically and the shell is constituted by disordered spins which are the origin of the observed spin glass behavior at very low temperatures. Moreover, for longer milling times, a ferromagnetic contribution rises. By total magnetic scattering we would like to obtain not only the local structure of our nanoparticles but also their local magnetic structure and thus, understand the full map of short range magnetic correlations. In fact, for certain applications, in particular biomedicine, it is very important to control these interactions in order to tune the agglomeration of the nanoparticles.