  We report a robust method of stabilizing a laser to the frequency of an
atomic transition using a hollow cathode lamp. In contrast to the standard
dichroic atomic vapor laser lock (DAVLL) method, which uses dichroism induced
by a longitudinal magnetic field, we employ birefringence induced by a
transversal magnetic field. We applied this method to the $(5s^2)\ {}^{1}S_{0}
- (5s5p)\ {}^{1}P_{1}$ transition (461 nm) of Sr. Although the hollow cathode
is made of ferromagnetic material, we successfully applied a magnetic field of
sufficient strength to obtain an error signal with a theoretical maximum slope.
This method may be applied to other hollow cathode lamps of different atomic
species.
