The magnetism of the single crystal Cr1=3NbS2, which exhibits chiral soliton lattice (CSL) state,
is investigated. The magnetization displays strong magnetic anisotropy when the field is applied
perpendicularly and parallel to the c-axis in low field region (H < HS, HS is the saturation field).
The critical exponents of Cr1=3NbS2 are obtained as β = 0.370(4), γ = 1.380(2), and δ = 4.853(6),
which are close to the theoretical prediction of three-dimensional Heisenberg model. Based on the
scaling equation and the critical exponents, the H ? T phase diagram in the vicinity of the phase
transition is constructed, where two critical points are determined. One is a tricrtical point which
locates at the intersection between the CSL, forced ferromagnetic (FFM), and paramagnetic (PM)
states. The other one is a critical point situated at the boundaries between CSL, helimagnetic (HM),
and PM states.