The minimum of the free energy occurs close to the h=0 solution m=m\ns0(θ)≡√3(1−θ), and writing m=m\ns0+δm we find δm to linear order in h as ...The minimum of the free energy occurs close to the h=0 solution m=m\ns0(θ)≡√3(1−θ), and writing m=m\ns0+δm we find δm to linear order in h as δm(θ,h)=h/2(1−θ).