Study On Magnetic Meterial With Spin Crossover Properties

Molecular spin crossover is a very interesting phenomenon,which has attracted attention of many researchers.In this paper,we study the effect of size on mag netic properties of spin-crossover complexes.Microemulsions technique have be en used for preparation of spin crossover(SCO)with different size by changing the dosage of surfactant.The spin transition temperature(Tc ↑、Tc ↓)and hys teresis loop were characterized by DSC SQUID.The results indicate that the s pin transition temperature(Tc ↑、Tc ↓)increasing;hysteresis loop(Δ)narrowing with the reducing size of SCO complexes.We can prepare the SCO complexe s with the speific spin transition temperature or hysteresis loop by this mean.I n second part,we prepare the polystyrene(PS)microsphere modified by acrylic acid(AA)and grafted with 4-amino-4H-1,2,4-triazole,then we get the spin cros sover complex-polystyrene microsphere by self-assembly reaction with Fe(Ⅱ).The modofied polystyrene microsphere and spin crossover complex-polystyrene microsphere were characterized by FTIR.The spin transition temperature(Tc↑、Tc ↓)and hysteresis loop were characterized by DSC SQUID.The results indicate that spin transition temperature(Tc ↑＝301 K,Tc ↓ ＝293 K)with a h ysteresis loop Δ=8 K.