Magnetism at the surface of the Heisenberg ferromagnet EuS

The critical exponent β1 of the surface of the isotropic Heisenberg ferromagnet EuS has been determined with spin-polarized low-energy electron diffraction (SPLEED): We find β1=0.72±0.03, a value which differs significantly from theoretical estimates. Reasons for this discrepancy will be discussed. Spin-polarized electron energy loss spectroscopy (SPEELS) shows intra-atomic and inter-atomic transitions. We report the first observation of the surface red shift of the 4f7-5dt2g absorption edge with EELS. This shift is found to be identical to that of the bulk as measured by optical absorption. © 1987 Elsevier Science Publishers B.V. (North-Holland Physics Publishing Division).