Synchrotron X-ray diffraction studies on magnetic materials in high magnetic fields

Non-resonant X-ray diffraction measurements on two kinds of magnetic materials were performed at the BL19LXU on SPring-8 in high magnetic fields. Magnetic reflections were observed in the metamagnet FeCl2·2H2O in the antiferromagnetic (AF) and the field-induced intermediate (I) phases. The field dependence of these reflections evidences a coexistence of the AF and I phases in a wide region of magnetic field when the field is decreased from the I phase. The lattice modulations in the field-induced magnetic phase of the spin-Peierls compound CuGeO3 were studied. The field dependence of the incommensurability measured up to 15 T is reproduced by the theory developed by Buzdin et al