GIANT MAGNETORESISTANCE IN URANIUM INTERMETALLICS - AB-INITIO CALCULATIONS FOR U2PD2IN AND U2PD2SN

Among the magnetic uranium intermetallic compounds, a considerable num ber is exhibiting field induced magnetic phase transitions. Such trans itions are frequently accompanied by giant magnetoresistance (GMR) eff ects. On the basis of density functional calculations we predict GMR t o be present in the recently discovered ternary compounds U2Pd2In and U2Pd2Sn. In particular, it is shown by this exemplary calculation that GMR in 5f intermetallics can be produced by topological changes of th e Fermi surface even if the size of the Brillouin zone is invariant un der the metamagnetic transition. The possibility of an inverse GMR eff ect is demonstrated without assuming any spin dependence in the scatte ring. No qualitative changes of the results are found if a moderately spin dependent scattering is introduced.