Noncollinearity of Mn spin in ferromagneticPtFe alloy: a nuclear orientation study

The low-temperature nuclear orientation of54Mn in ferromagnetic Pt+5 at% Fe has been studied in the temperature range 4–50 mK andin the external magnetic field range 0.5–8.5 T. A considerable noncollinearity of Mn magnetic moments with respect to the bulk magnetization direction has been found in the wholeBext range. A model based on the Heisenberg Hamiltonian in the first neighbour approximation is proposed, which fully describes our experimental data.