X-ray magnetic spectroscopy at high pressure: performance of SPring-8 BL39XU.

An X-ray magnetic circular dichroism experiment under multiple extreme conditions, 2 <or= T <or= 300 K, H <or= 10 T and P <or= 50 GPa, has been achieved at SPring-8 BL39XU. A combination of the high-brilliant X-ray beam and a helicity-controlled technique enabled the dichroic signal to be recorded with high accuracy. The performance is shown by the outcome of pressure-induced ferromagnetism in Mn(3)GaC and the pressure-suppressed Co moment in ErCo(2). Two technical developments, a tiny diamond anvil cell inserted into a superconducting magnet and in situ pressure calibration using 90 degrees Bragg diffraction from a NaCl marker, are also presented. X-ray magnetic spectroscopy under multiple extreme conditions is now opening a new approach to materials science.