Magnetic dichroism in core-level photoemission from Gd(0001)

Abstract

This work reports on magnetic dichroism in photoemission from the Gd 4l(l=s,p,d, f) core level of in-plane magnetized Gd films excited with linearly, circularly, and unpolarized light. Thin Gd films of about 100 ML thickness were evaporated onto a W(110) substrate at room temperature, and subsequently annealed to 700 K to form an ordered layer exhibiting a (0001) surface. The dichroism measurements were performed by physically rotating the sample azimuth so as to change the direction of the magnetization axis relative to the incident light. The magnetic dichroism asymmetries were obtained by calculating the normalized difference between spectra obtained with the two mutually orthogonal orientations of the magnetization. Strong asymmetries were observed, even if exciting the spectra by means of unpolarized light. The experimental results are compared to three-step photoemission cluster calculations based on a relativistic full potential algorithm respecting magnetic exchange.