We report mSR experiments carried out on a series of heavy-electron pseudobinary compounds U(Pt1-xPdx)3 (x<=0.05). For x<=0.005 the zero-field muon depolarisation is described by the Kubo-Toyabe function. However the temperature variation of the Kubo-Toyabe relaxation rate does not show any sign of the small-moment antiferromagnetic phase with TN~6 K (signalled by neutron diffraction), in contrast to previous reports. The failure to detect the small ordered moment suggests it has a fluctuating (> 10 MHz) nature, which is consistent with the interpretation of NMR data. For 0.01<=x<=0.05 the muon depolarisation in the ordered state is described by two terms of equal amplitude: an exponentially damped spontaneous oscillation and a Lorentzian Kubo-Toyabe function. These terms are associated with antiferromagnetic order with substantial moments. The Knight-shift measured in a magnetic field of 0.6 T on single-crystalline U(Pt0.95Pd0.05)3 in the paramagnetic state shows two signals for B perpendicular to c, while only one signal is observed for B||c. The observation of two signals for B perpendicular to c, while there is only one muon localisation site (0,0,0), points to the presence of two spatially distinct regions of different magnetic response.
@article{arxiv.cond-mat/9904349,
title = {Magnetism in heavy-fermion U(Pt,Pd)3 studied by mSR},
author = {R. J. Keizer and A. de Visser and A. A. Menovsky and J. J. M. Franse and A. Amato and F. N. Gygax and M. Pinkpank and A. Schenck},
journal= {arXiv preprint arXiv:cond-mat/9904349},
year = {2009}
}
Comments
25 pages including 12 figures (PS), J. Phys.: Condens. Matter, in print