Magnetic ordering in a supercooled Co-Pd melt studied by muon-spin rotation

Liquid samples of Co80Pd20 were cooled below their liquidus temperature Tl and supercooled towards the paramagnetic-ferromagnetic transition temperature TC(l) by means of the Electromagnetic Levitation (EML) technique. Muon-Spin Rotation (μSR) measurements were used to determine the spin precession frequency f and the transverse muon-spin relaxation rate Γ in the liquid supercooled sample at temperatures T > TC(l). Γ increases by a factor of 5 when T approaches TC(l), indicating large spin fluctuations caused by the onset of spontaneous magnetization. The temperature dependence of the inverse frequency shift Δf−1 reflects a Curie-Weiss behaviour of the paramagnetic susceptibility. The experiments strongly suggest the existence of ferromagnetic ordering in a liquid metal.