Investigating the Low Temperature Magnetic Transition in the New Breathing Pyrochlore CuAlCr4S8

Geometrically frustrated systems have been studied extensively over the last three decades. One archetype for geometrical frustration is magnetic ions decorating corner-sharing tetrahedra. The breathing pyrochlore structure has an alternating array of small and large tetrahedra and this unique combination of tetrahedral geometry and bond alternations allows for a wealth of exotic magnetic behavior. We are proposing to use WISH to investigate the magnetic transition at 20 K in our powder sample of the new breathing pyrochlore CuAlCr4S8. The magnetic susceptibility, heat capacity, and x-ray data show clear signs of a transition at 20 K with magnetic origin, but this transition is not well understood as of yet. The proposed experiment will allow us to search for magnetic Bragg peaks and diffuse scattering below 20 K and will provide much insight on the magnetic ground state in CuAlCr4S8.