  Atomic transitions of alkali metals for which the condition $F_e-F_g = \pm2$
is satisfied have null probability in a zero magnetic field, while a giant
increase can occur when an external field is applied. Such transitions, often
referred to as magnetically-induced (MI) transitions, have received interest
because their high probabilities in wide ranges of external magnetic fields
which, in some cases, are even higher than that of usual atomic transitions.
Previously, the following rule was established: the intensities of MI
transitions with $\Delta F=\pm2$ are maximum when using respectively
$\sigma^\pm$ radiation. Within the same ground state, the difference in
intensity for $\sigma^+$ and $\sigma^-$ radiations can be significant, leading
to magnetically induced circular dichroism (MCD), referred to as type-1. Here,
we show that even among the strongest MI transitions, $i.e$ originating from
different ground states for $\sigma^+$ and $\sigma^-$, the probability of MI
transition with $\Delta F = + 2$ is always greater, which leads to another type
of MCD. Our experiments are performed with a Cs-filled nanocell, where the
laser is tuned around the D$_2$ line; similar results are expected with other
alkali metals. Theoretical calculations are in excellent agreement with the
experimental measurements.
