HIGH-PRESSURE NEUTRON AND MAGNETIZATION INVESTIGATIONS OF THE MAGNETIC-ORDERING IN CESB

High-pressure magnetization and neutron-diffraction experiments have been performed on CeSb under hydrostatic pressure up to 21 kbar in the temperature range 3 - 32 K. The magnetic ordering in CeSb is very sensitive to hydrostatic pressure. The Neel temperature T(N) changes from 16 K at P = 1 bar to 31 K at P = 21 kbar. The stability ranges in temperature of the so-called antiferroparamagnetic (AFP) phases decrease continuously with pressure and disappear completely above P = 10 kbar. At P = 2.5 kbar, the type-I phase stabilizes at T(N) and the transition at T(N) crosses over from first to second order giving rise to the critical end point at P = 2.5 kbar, T = 18 K. At P = 10 kbar two phases with magnetic ordering sequences (+ + - - + -) and (+ + - - + - - + + -) of the ferromagnetic (010) planes are successively observed between type-I and type-IA phases. The results have been discussed in terms of the p-f mixing model.