Determination of the easy axis of magnetization by X-ray powder diffraction

A sample holder for X-ray powder diffraction was constructed with a permanent magnet which supplies a field of 1 T on its surface. A preferred orientation in the positions of the single domain grains can be obtained by using an external magnetic field in a temperature-dependent X-ray diffraction equipment. From the change in the line intensities, the direction of the easy magnetization of a ferro- or ferrimagnetic order can be determined below the Curie temperature. A spin reorientation may also be observed in the ordered state by performing the measurements at variable temperature.