THE MAGNETIZATION OF ADSORBED HE-3 STUDIED BY RENORMALIZATION-GROUP TECHNIQUES

The magnetic and thermodynamic properties of adsorbed He-3 have drawn considerably attention in the last few years. The experiments have bee n refined recently using different substrates and applied fields. In t he ferromagnetic regime the system has been described by the Heisenber g Hamiltonian and its thermodynamics properties are well described at high temperatures by a Heisenberg series expansion. The very low tempe rature properties are described by calculations using spin wave theory . We present here real space renormalization group calculations that a re valid in both domains and specially for T approximate to J, and a n ew approach which takes Into account the finite size of the substrate.