SSG or SFM state in CoFe2O4CoFe2O4 nano-agglomerates fabricated by micro-emulsion method

We report on magnetic properties of CoFe2O4CoFe2O4 nano-agglomerates obtained by micro-emulsion technique under specific conditions. The samples form a unique morphology as observed by transmission electron microscopy and scanning electron microscopy investigations. Concerning magnetic properties, they exhibit a considerable coercivity of almost 1 T at 2 K, which continuously decreases up to the characteristic temperature, Tg=350K. The temperature dependence of the zero-field cooled (ZFC) and field cooled (FC) magnetization, respectively, is furcated at the TgTg, and the temperature dependencies of the a.c. susceptibility exhibit a frequency-dependent maximum at ∼Tg∼Tg. The observed behavior is discussed in terms of the super-spin-glass (SSG) and the super-ferromagnetic (SFM) regime considering the morphology of the nano-agglomerates.