InternationalReciprocal spaceTables for Crystallography Volume B Edited by U. Shmueli © International Union of Crystallography 2006 |
International Tables for Crystallography (2006). Vol. B. ch. 1.2, p. 11
## Section 1.2.5.2. Magnetic scattering |

The interaction between the magnetic moments of the neutron and the unpaired electrons in solids leads to magnetic scattering. The total elastic scattering including both the nuclear and magnetic contributions is given by where the unit vector describes the polarization vector for the neutron spin, is given by (1.2.4.2*b*) and **Q** is defined by is the vector field describing the electron-magnetization distribution and is a unit vector parallel to **H**.

**Q** is thus proportional to the projection of **M** onto a direction orthogonal to **H** in the plane containing **M** and **H**. The magnitude of this projection depends on , where α is the angle between **Q** and **H**, which prevents magnetic scattering from being a truly three-dimensional probe. If all moments are collinear, as may be achieved in paramagnetic materials by applying an external field, and for the maximum signal (**H** orthogonal to **M**), (1.2.5.2*a*) becomes and (1.2.5.1*a*) gives and for neutrons parallel and antiparallel to , respectively.