Abstract: Nondestructive cryogenic preservation has been an important research topic in cryobiology. Organisms are mostly composed of aqueous solution. Common methods involve the use of an ultra-rapid cooling rate or a very high concentration of cryoprotectants. Unfortunately, adding cryoprotectants introduces impurities for biomaterials themselves and ultrarapid freezing is very difficult to obtain the same cooling rate for the surface and interior of big samples. The influence of ice crystal formation process in KMnO4 solution by alternated magnetic field was studied under the condition of low cooling rate. Alternated magnetic field was produced based on series resonance. This study shows that 50 kHz alternated magnetic field can suppress ice crystal growth in the solution, and salty ice formed. The result of low freezing rate cryopreservation easy achieved is of great significance, and useful in practical applications.

Key words: cryopreservation, ice crystal, series resonance, virtual instrument