2520
The variation of the surfactants having surface - binding functional groups modified not only the static magnetization but also the dynamics of the recovery of the magnetization occurring via spin - lattice relaxation in the photoexcited Fe3O4 nanocrystals .
 Chemical: Fe3O4
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: Fe3O4 
Answer:
 Chemical: Fe3O4