High concentration ferronematics in low magnetic fields
  We investigated experimentally the magneto-optical and dielectric properties of magnetic-nanoparticle-doped nematic liquid crystals (ferronematics). Our studies focus on the effect of the very small orienting bias magnetic field $B_{bias}$, and that of the nematic director pretilt at the boundary surfaces in our systems sensitive to low magnetic fields. Based on the results we assert that $B_{bias}$ is not necessarily required for a detectable response to low magnetic fields, and that the initial pretilt, as well as the aggregation of the nanoparticles play an important (though not yet explored enough) role. 
T. T\'oth-Katona, P. Salamon, N. \'Eber, N. Toma\v{s}ovi\v{c}ov\'a, Z.   Mitr\'oov\'a, P. Kop\v{c}ansk\'y
cond-mat.soft