NONEQUILIBRIUM FCC PHASE AND VALENCE FLUCTUATION IN IMMISCIBLE YB-CE ALLOY PRODUCED BY MECHANICAL ALLOYING

Using mechanical alloying (MA), non-equilibrium fcc Yb-Ce has been obt ained from immiscible Yb and Ce metals. The new phase formation and th e lattice contraction are confirmed by the X-ray diffraction. Magnetic and low temperature specific heat measurements give the effective mag netic moment of about 4 mu(B) and the enhancement of electronic specif ic heat coefficient, 600 mJ.mol-1 K-2. These results indicate that the valence change of Yb from divalent to trivalent is induced in MA proc ess and contributes to the new phase formation.