Low temperature specific heat of beryllium compounds of the first transition metal series between VBe2 and FeBe2

Specific heat measurements have been performed on TBe2 and (T,T')Be2 beryllium compounds, where T and T' are neighbour transition metals of the first series. The temperature range investigated is 1.5. to 4.2K. For the paramagnetic alloys with 5<e/a<7, there is a regular behaviour of the electronic specific heat coefficient gamma with a minimum at e/a=6.12 and, the two half d bands with opposite spin directions are equally unfilled in agreement with the paramagnetic behaviour of the compounds. In the electronic concentration range, 7<e/a<7.6, the large peak of gamma at about e/a=7.16 is mainly ascribed to clustering effects due to the appearance of ferromagnetism. Above e/a=7.6, gamma decreases down to a minimum at e/a=8 where there is a transition from weak to strong ferromagnetism.