Magnetic blocking in ferronematic liquid crystals

It is self-evident that ferrofluid particles added to liquid crystals to form ferronematics must be blocked at room temperature in order to be able to orient the ferronematics at low fields (∼10-2 T). Magnetite particles ∼10 nm are commonly used, but their blocking temperature is ∼100 K. We will show that they are indeed paramagnetic in the ferrofluid, but become blocked when added to the liquid crystal