Magnetic properties of photosynthetic materials - a nano scale study

Photosynthetic materials form the basis of quantum biology. An important attribute of quantum biology is correlation and coherence of spin states. Such correlated spin states are targets of static magnetic field. In this paper, we report magnetic properties and spectroscopically realizable static magnetic field effect in photosynthetic materials. Two classes of nano-scale assembly of chlorophyll (NC) are used for such a study. Magnetic measurements are made using a superconducting quantum interference device (SQUID). Both ferromagnetic and superparamagnetic states are observed in NC along with a blocking temperature around 250 K. Low temperature quantum (liquid nitrogen) spectroscopy is employed to see how optical transitions are affected in presence of static magnetic field. Plausible practical application aspects of magnetic properties of this optically active material are discussed in the text.