Temperature behavior of the local magnetization vectors in ferromagnetic inverted opal-like structures

Abstract

The behavior of magnetization in films of ferromagnetic inverted opal-like nanostructures based on cobalt and nickel is studied. The remagnetization curves M(H) and temperature dependences M(T) in the ranges of H from–50000 to +50000 Oe and T = 5–350 K are measured by magnetometry using a superconducting quantum interference device (SQUID-magnetometry). It is demonstrated that at T > 70 K, the total magnetization of the inverted nanostructures is composed of four local magnetizations, the vectors of which are oriented along the 〈111〉 anisotropy axes of a spatial opal-like structure. At low temperatures, the anisotropy of the film is found to make an additional significant contribution. The critical magnetic fields corresponding to reorientation of the local magnetization vectors along the 〈111〉 anisotropy axes are determined from the M(H) experimental curves. The data obtained for ferromagnetic inverted opal-like nanostructures are compared with the behavior of magnetization in continuous nickel and cobalt films.