Applications of superconducting trapped field magnets for x-ray scattering experiments*

Two long standing problems in x-ray and neutron scattering studies in applied magnetic fields are, 1) limited optical access and 2) practical impossibility to apply magnetic field parallel to x-ray (neutron) momentum transfer. In order to overcome these obstacles we have developed an application of Type-II superconducting magnets. In this approach, a small and thin plate-like single crystal sample is mounted on the surface of a melt-textured superconductor (SC). The SC is magnetized by cooling it from temperature above its superconducting critical temperature ($T_{c})$ in an applied magnetic field. Below $T_{c}$, magnetic flux gets trapped inside the SC disk after the removal of the external magnetic field. The SC disk acts as a permanent magnet with applied field normal to the flat surface of the disk providing unrestricted optical access to the entire hemisphere allowing a magnetic field parallel to the x-ray momentum transfer.