We report the results of a search for pair production of scalar bottom quarks (inline imageinline image) and scalar third-generation leptoquarks (LQ sub(3) in 5.2 fbsuper-1 of inline imageinline image collisions at the D0 experiment of the Fermilab Tevatron Collider. Scalar bottom quarks are assumed to decay to a neutralino (inline imageinline image) and a b quark, and we set 95% C.L. lower limits on their production in the (inline imageinline image, inline imageinline image) mass plane such as inline imageinline image for inline imageinline image and inline imageinline image for inline imageinline image. The leptoquarks are assumed to decay to a tau neutrino and a b quark, and we set a 95% C.L. lower limit of 247 GeV on the mass of a charge-1/3 third-generation scalar leptoquark.)