Magnetization under High Pressure in MnSi

The magnetization M(H) has been measured in the weakly helimagnetic itinerant compound MnSi under high pressure up to 10.2 kbar and high magnetic field up to 9 Tesla. We interpret the simultaneous decrease under pressure of the saturated magnetization, $p_s$, and the Curie temperature, $% T_c$ in the frame of the self-consistent renormalization theory (SCR) of spin fluctuations. From the analysis of the so-called Arrot-plot ($H/p [ H,T ] $ versus $p^2[ H,T ] $) and the respective volume dependence of $p_s$ and $T_c$, we estimate the evolution of the characteristic spin fluctuation temperatures, $T_0$ and $T_A$ when the system approaches its critical pressure, $P_c$=15 kbar, corresponding to the disappearance of the long range magnetic order at T=0.