Ultrahigh-vacuum-compatible diffractometer for soft X-ray scattering

Abstract

We report on the development and the performance of a new instrument for soft X-ray scattering experiments. A ultrahigh- vacuum-compatible two-circle diffractometer was realized by mounting two differentially pumped rotary platforms on top of a cylindrical vacuum chamber. The concentric rotations of the detector and sample are driven by externally-mounted motors and gears. The vacuum chamber itself was designed to accommodate the instruments for surface treatment and in-situ film growth. A special cryo-system was also designed to allow changing the sample temperature from 8 K to 480 K. During measurements, a magnetic field of +/- 1500 Oe can be applied by using an electromagnet along all directions in the scattering plane. The synchronous rotation of the electromagnet with that of the sample is provided by using a separate rotary driver. All functions of the experimental setup have been extensively tested by measuring the ferromagnetic property of the CoFe/IrMn exchange-biased thin film and the antiferromagnetic ordering of LaSr2Mn2O7.