NMR study of MnAs at atmospheric and high pressures

Abstract Zero-field NMR of MnAs has been observed as a function of temperature T and pressure. In the ferromagnetic NiAs phase the frequencies of the 55 Mn and 75 As NMR show a T 5/2 dependence below 160 K, which is compared with the empirical T n power law in usual magnetic materials. Above about 4 kbar a broad NMR line is observed and is assigned to the helical magnetic state of MnP type phase.