A MODEL FOR THE HEAVY-FERMION BEHAVIOR OF YMN2 - INFLUENCE OF FRUSTRATION ON THE SPIN FLUCTUATION SPECTRUM

We show that the magnetic properties of frustrated itinerant systems c an be described by a peculiar shape of the q-dependent susceptibility. We justify the fact that the spin fluctuation spectrum is especially broad in this case. This spectrum is used to calculate the spin fluctu ation contribution to the specific heat; we show that this contributio n can be very large close to a magnetic-non-magnetic instability. Comp arison with recent experimental results on YMn2 is made and the simila rities of this compound with the 4f heavy-fermion compounds are emphaz ied.