Thermal stability of ledge-type L10-FePt/Fe exchange-spring nanocomposites for ultrahigh recording densities

Long-term thermal stability is crucial for magnetic nanoparticles in ultrahigh density magnetic recording. For ledge-type exchange-spring nanocomposites consisting of a hard magnetic L1(0)-FePt part and a soft magnetic Fe part of more extended horizontal size, the minimum energy barriers for thermal reversal between equilibrium states of the hysteresis loops are determined using a nudged-elastic-band path approach. The field dependence of the energy barrier can be described approximately by power laws. It turns out that nanopatterns of isolated ledge-type L1(0)-FePt/Fe composite elements or isolated L1(0)-FePt nanodots covered by a thin Fe film are well-suited in realizing ultrahigh recording densities. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.3001589]