A Mu-Sr And Neutron Polarization Analysis Study Of Mn Moment Delocalization In Fe Substituted Ymn2

Neutron polarisation analysis measurements reveal antiferromagnetic spin correlations persisting to temperatures of 120 K in Pauli paramagnetic Y(Mn(1-x)Fe(x))2, 0.03 less-than-or-equal-to x less-than-or-equal-to 0.05. The mean moment at the Mn(Fe) site is found to be 0.2-mu-B. Transverse field mu-SR is characterised by weak exponential damping with a rate of 0.02-mu-s-1 at 300 K increasing according to the power law T-0.75 to only 0.16-mu-s-1 at 12 K. It is suggested that these results are consistent with a slowing down of longitudinal spin fluctuations at the Mn site as temperature decreases.