Pressure effect on thermopower of Y1-xGdxCo2Y1-xGdxCo2 alloy system

Thermopower of Y1-xGdxCo2Y1-xGdxCo2 pseudobinary compounds has been measured at temperatures from 1.5 to 300 K under hydrostatic pressure up to 2 GPa and in magnetic field 0–15 T. In the inhomogeneous and paramagnetic regions of the phase diagram the main contribution to the electronic transport is related to the strong static magnetic fluctuations, which arise due to interplay of structural disorder within Gd-sublattice and Co-3d itinerant electron metamagnetism. This complex magnetic disorder brings about novel transport phenomena, such as anomalous positive magnetoresistance found in ferrimagnetic state of the alloys. The low-temperature thermopower is almost independent of alloy composition in the ferrimagnetic range of the phase diagram (x>0.3x>0.3) indicating that the alloying does not change electronic structure of the compounds in a close vicinity of Fermi energy. However, the thermopower shows substantial variation with the composition in the inhomogeneous and in the paramagnetic regions of the phase diagram reflecting evolution of the magnetic structure with the composition.