The SPME for the spin part of the magnetic operator is $$ \langle k_{a}\vert\vert O(M\lambda ,s)\vert\vert k_{b}\rangle = $$ $$ =\sqrt{\lambda (2\lambda +1)}< j_{a}\vert\vert [Y^{\lambda -1}(\hat{r})\otimes\mathbf{s}\,]^{\lambda }\vert\vert j_{b}> < k_{a}\vert r^{\lambda -1}\vert k_{b}>g^{s}_{q}\mu _{N}, $$ $$ = \sqrt{\lambda (2\lambda +1)}\, \sqrt{(2j_{a}+1)(2j_{b}+1)(2\lambda +1)}\left\{\begin{array}{ccc} {l _{a}}& {1/2} & {j_{a}}\\ {l _{b}}& {1/2} & {j_{b}}\\ {\lambda -1} & {1} & {\lambda}\end{array}\right\} $$ $$ \times \langle l _{a}\vert\vert Y^{\lambda -1}(\hat{r})\vert\vert l _{b}\rangle\langle\vert\vert \mathbf{s}\vert\vert s\rangle\langle k_{a}\vert r^{\lambda -1}\vert k_{b}\rangle g^{s}_{q}\mu _{N}, $$ where $$ \langle\vert\vert \mathbf{s}\vert\vert s\rangle = \sqrt{3/2}. $$