Not relevant to cryonics. "Super-cooling" is not a neologism, it means that the water didn't freeze when they cooled the organs down to -3 degrees C. This is not extendable to lower temperatures.
It might help, though - if you suddenly stop applying the magnetic fields, then it might freeze more abruptly than if you simply lower the temperature. That could reduce the extent of crystallization and thus damage.
This is great, by using small interlocking magnetic fields, you can keep the water in a higher vibrational state, allowing a "super-cooling" without getting crystallization and cell rupture
Subzero 12-hour Nonfreezing Cryopreservation of Porcine Heart in a Variable Magnetic Field
"invented a special refrigerator, termed as the Cells Alive System (CAS; ABI Co. Ltd., Chiba, Japan). Through the application of a combination of multiple weak energy sources, this refrigerator generates a special variable magnetic field that causes water molecules to oscillate, thus inhibiting crystallization during ice formation18 (Figure 1). Because the entire material is frozen without the movement of water molecules, cells can be maintained intact and free of membranous damage. This refrigerator has the ability to achieve a nonfreezing state even below the solidifying point."
http://mobile.journals.lww.com/transplantationdirect/_layouts/15/oaks.journals.mobile/articleviewer.aspx?year=2015&issue=10000&article=00005#ath