2. Experimental section Spinel magnetite nanocrystals were prepared by a sonochemical method developed in our group [25,26]. Fe3O4 nanoparticles with size less than 10 nm were used as the core of magnetic
2. Experimental section Spinel magnetite nanocrystals were prepared by a sonochemical method developed in our group [25,26]. Fe3O4 nanoparticles with size less than 10 nm were used as the core of magnetic