  We report on magnetisation and magneto-capacitance measurements in the
Bi1-xLaxFeO3 series for 0 < x < 0.15. We confirm that doping with La reduces
the threshold magnetic field Hc for cancelling the magnetic spiral phase, and
we show that Hc decreases as the La content increases up to x=0.15, which is
the highest concentration for maintaining the non-centrosymmetric rhombohedral
structure of BiFeO3. Measurements of the dielectric constant as a function of
magnetic field in the series also show a maximum magneto-capacitance for
x=0.15.
