Eur. Phys. J. B 76, 209-213 (2010)
https://doi.org/10.1140/epjb/e2010-00191-5

Longitudinal polarization analysis in small-angle neutron scattering

¹ Technische Physik, Universität des Saarlandes, Postfach 151150, 66041 Saarbrücken, Germany
² Institut Laue-Langevin, 6 Rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9, France
³ Departamento de Física, Universidad Pública de Navarra, Campus de Arrosadía, 31006 Pamplona, Spain
⁴ Department of Materials Engineering, Monash University, Clayton, Victoria, 3800, Australia

Corresponding author: ^a andreas.michels@uni.lu

Received: 4 March 2010
Revised: 19 April 2010
Published online: 24 June 2010

Abstract

Due to recent progress in the development of ³He spin filters, it has only now become possible to perform routinely longitudinal (one-dimensional) neutron-spin analysis (POLARIS) in small-angle neutron scattering (SANS) experiments. It is the purpose of this article to provide a brief introduction into the technique and to discuss first experimental data. In particular, for the most common scattering geometry where the applied magnetic (guide) field is perpendicular to the incident neutron beam, we write down the equations for the non-spin-flip and spin-flip SANS cross sections of a bulk ferromagnet, and we discuss the various angular anisotropies and asymmetries along with some selected experimental results on an FeCr based soft magnetic nanocrystalline alloy. In particular, we show that the analysis of the spin-flip data allows one to obtain the magnitude-squares of the three vector (Fourier) components of the magnetization.