Heat capacity measurements of itinerant electron magnetism in Y3Ni13−xCOxB2 system

The heat capacity of the Y3Ni13−xCoxB2 series has been measured from 300 mK to RT. The magnetic ordering phase transitions have been characterized as second-order type and the Tc's determined. The electronic contribution to the low-temperature heat capacity for x=0 yields an electronic constant γ=54 mJ mol K2, which is higher than those of YNi5 and YNi4B, proving experimentally that its density of states at the Fermi surface is larger than in those other compounds. The substitution of Ni by Co increases γ linearly. Electronic band calculations could explain these features.