Magnetic behavior of an array of cobalt nanowires

Cobalt nanowires have been electrodeposited into the pores of Anodisc(TM) alumina membranes after placing on one side a layer of sputtered copper, which acts as electrode and substrate during the electrodeposition. Nanowires are 60 mm long, 170-220 mu m in diameter depending on the size of the pores of the alumina membrane. This array of nanowires exhibits uniaxial magnetic anisotropy related to the particular shape of each individual nanowire. On the contrary to the expected behavior in a uniaxial magnetic system, the coercivity of the array exhibits a maximum when the applied field is in a perpendicular direction with respect to the easy axis. This magnetic behavior is analyzed considering dipolar interactions among nanowires, and the magnetization of the array is obtained as a function of the magnetic characteristics of each nanowire using an iterative method. (C) 1999 American Institute of Physics. [S0021-8979(99)63208-X].