A current loop in a magnetic field is in equilibrium in two orientations one is stable and another unstable.

When a current loop is placed in a magnetic field it experiences a torque. It is given by

$\overrightarrow \tau = \overrightarrow M \times \overrightarrow B$ = MB sin$\theta$

where, $\overrightarrow M$ is the magnetic moment of the loop and $\overrightarrow B$ is the magnetic field.

If $\theta$ = 0^o $\Rightarrow$ $\tau$ = 0 (stable equilibrium)

If $\theta$ = 180^o $\Rightarrow$ $\tau$ = 0 (unstable equilibrium)