Uniform magnetic chains of hollow cobalt mesospheres from one-pot synthesis and their assembly in solution

Magnetic chains up to 10 mu m in length formed of hollow cobalt mesospheres (480-850 nm) with a 60 nm thick shell are synthesized by a new soft-assembly protocol. The obtained chains show a saturation magnetization of 37.5 emu g(-1), a remnant magnetization of 1.55 emu g(-1), and a coercivity of ca. 66 Oe at 300 K. A possible mechanism for the formation of the chainlike hollow structures is proposed.