Magnetic circular dichroism and orbital momentum coupling in4dphotoemission from Gd(0001)

Abstract
Strong magnetic circular dichroism (MCD) has been observed in 4d core-level photoemission (PE) from magnetized Gd(0001) metal, in agreement with an atomic many-particle description. This solves a long-standing controversy on the correct interpretation of the 4d PE spectrum of Gd. We show that MCD depends on the spin and orbital-momentum coupling in the final state, leading to MCD effects of opposite sign for high and low total angular momenta, respectively. The spin of the excited state can be assigned from MCD, and we discuss its role in the lifetime broadening of PE peaks.