There are often several different methods of synthesizing materials, and in lots of cases they arrive at the same result. Sometimes the experiments you want to do will depend on your growth method, though: for instance, the polycrystalline samples you get from solid state reactions can be good for x-ray or neutron diffraction studies. If you want to examine transport properties, though, especially anisotropic ones, single crystals are frequently much more useful. Arguably the simplest way to get single crystals of usable sizes is just to seal the precursor materials in an evacuated ampoule, heat it up, and then slowly cool it down. Crystals will nucleate and grow on their own out of the melt, and you can centrifuge away the remaining liquid. There are a few improvements you can make to the growth parameters by controlling nucleation with a thermal gradient, but the basic idea is the same. This is usually how single-crystal Fe-based superconductors are grown.