X-ray powder diffractometer for in situ structural studies in magnetic fields from 0 to 35 kOe between 2.2 and 315 K

A technique for studying magnetic field induced structural changes at the atomic resolution is described. The instrument involves the coupling of a high resolution laboratory x-ray powder diffractometer, a helium flow cryostat, and a split-coil superconducting magnet allowing for in situ structural studies in a magnetic field between 0 to 35 kOe, and a temperature between 2.2 to 315 K. The data collected from a copper sample, which is used as a standard, at temperatures down to 4.3 K and in fields up to 10 kOe are presented. The ability to image massive magnetic field induced structural transformations is demonstrated utilizing powder diffraction data of Gd5Ge4 collected under both isothermal and isofield conditions at various temperatures below 15 K and magnetic fields up to 35 kOe. These results show the utility of our approach to obtain high precision structural information in the presence of a strong magnetic field. (C) 2004 American Institute of Physics.