Eur. Phys. J. Special Topics 208, 165-175 (2012)
https://doi.org/10.1140/epjst/e2012-01617-0

Regular Article

The influence of surface roughness in X-ray resonant magnetic reflectivity experiments

¹ CNR-INFM TASC National Laboratory, Area Science Park-Basovizza, 34149 Trieste, Italy
² European Synchrotron Radiation Facility, 6 rue Jules Horowitz, Bote Postale 220, 38043 Grenoble, France
³ Dipartimento di Ingegneria dei Materiali e dell’Ambiente, Università di Modena e Reggio Emilia, via Vignolese 905, 41100 Modena, Italy

^a e-mail: verna@tasc.infm.it

Received: 26 November 2011
Revised: 23 March 2012
Published online: 15 June 2012

Abstract

We present simulations of X-ray resonant magnetic reflectivity (XRMR) spectra of the surface magnetic dead layer in La_1−xSr_xMnO₃ (LSMO) films that take in account the effect of different forms of roughness that can be encountered experimentally. The results demonstrate a method to distinguish between surface (morphological) roughness, and two generic kinds of magnetic roughness at the buried interface between the surface dead layer and the fully magnetic bulk part of the film. We show that the XRMR technique can distinguish between different types of magnetic roughness at the dead layer/bulk interface only if the sample surface is nearly atomically flat (the morphological roughness is one unit cell or less). Furthermore, to distinguish between the two types of magnetic roughness, the simulations show that fitting of XRMR spectra out to very high incidence angles must be performed. In the specific case of LSMO films with a dead layer with average thickness of 4 unit cells, this corresponds to an incidence angle > 50^∘.