Magnetic properties of Ce₃Pd₂₀Si₆ at very low temperatures

We have performed magnetization measurements of a single crystalline Ce₃Pd₂₀Si₆ down to 90 mK in fields up to 11 T. Two transitions were recognized in M(T) at low fields; a cusp at 0.27 K due to a magnetic transition, and an upward bending at ∼0.5 K that probably corresponds to a quadrupole transition. The latter critical temperature is found to be strongly enhanced in magnetic fields. The magnetization M(H) at 90 mK is strongly anisotropic above 0.6 T, and shows several sharp features associated with phase transitions. Interestingly, no appreciable anisotropy is found in the magnetic phase below 0.27 K and 0.6 T.