Magnetoresistivity studies of intermetallic uranium compounds and their impact on the exhibited phenomena

Robert Troć 

Polish Academy of Sciences, Institute of Low Temperature and Structure Research (INTiBS), Okólna 2, Wrocław 50-422, Poland

Abstract

In recent years the occurrence of a large reduction of the electrical resistivity upon application of a magnetic field, called as a giant magnetoresistvity (GMR)effect,first of all observed in some magnetic-multilayer systems like Fe/Cr or Co/Cu, has attracted much attentions due to the possible applications.

It turned out that GMR is also possible in various uranium based compounds which crystaliize in layered-like structures. In the latter case one should drive a given antiferromagnetic uranium compound through a metamagnetic (MT) transition towards an induced ferromagnetic aligment.This is connected with a reorientation of the 5f-magnetic moment, which can be also the origin of GMR effects in multilayers. Thus this causes a drastic reduction of the electrical resistivity, which may exceed even that of multilayer systems.The high resistance state in bulk uranium antiferromagnets is attributed to the reduction of effective carrier concentration or change in the FS topology by arising the Fermi level gapping. The transverse magnetoresistance may give also the overall information on the Fermi surface of such uranium based systems (with open or closed orbits)allowing to distinquish a compensated from an uncompensated kind of metal. For some uranium materials the temperature dependence of MR gives evidence of an enormous scattering due to the spin fluctuations being responsible for their superconducting properties.

Presentation: invited oral at E-MRS Fall Meeting 2005, Symposium B, by Robert Troć
See On-line Journal of E-MRS Fall Meeting 2005

Submitted: 2005-05-18 14:07
Revised:   2009-06-07 00:44
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