The variation of intensity of magnetisation (I) and the applied...

The variation of intensity of magnetisation (I) and the applied magnetic field intensity (H) for three magnetic materials ' $\mathrm{X}^{\prime}$, ${ }^{\prime} \mathrm{Y}^{\prime}$ and ' $\mathrm{Z}$ ' are shown in the graph as OX, OY and OZ respectivley. The materials ' $\mathrm{X}^{\prime},{ }^{\prime} \mathrm{Y}^{\prime}$ and ' $\mathrm{Z}$ ' respectively are