Angle and temperature dependence of magnetic circular dichroism in core-level photoemission from Gd(0001)

Abstract

Magnetic dichroism in core-level photoelectron emission from solids represents a promising new element-specific probe of surface and interface atomic structure and magnetic order. One way of measuring such effects is by using photoelectrons excited by circular polarized radiation, thus leading to magnetic circular dichroism (MCD) if the intensity with right-circular polarized (RCP) light is not equal to that with left-circular polarized (LCP) light. The spin-integrated photoelectron intensity in a certain emission direction also in general depends on the direction of the magnetization in a magnetic material. In fact, if the magnetization lies in a surface mirror plane, then inverting its direction can provide a second way of measuring MCD. Purely atomic theoretical models have been successful in explaining many aspects of such data. By varying the emission direction one also probes the geometric structure of the sample. But such MCD in photoelectron angular distributions (MCDAD) then has to be interpreted also in terms of photoelectron diffraction. Measuring the temperature dependence of such MCD effects also provides a useful tool for studying magnetic transition temperatures. The authors have here studied such effects in core-level emission from Gd(0001).