Reversal mechanisms and metastable states in magnetic nanoelements

Transmission electron microscopy and micromagnetic modeling have been used to study magnetization processes in small elongated magnetic elements with different end shapes. Their response to fields applied both parallel and perpendicular to the element long axes has been investigated with particular emphasis on the latter. A rich variety of magnetic states have been revealed and it is shown that very similarly shaped elements can respond quite differently; moreover the same element need not respond in the same way when subjected to repeated field cycles. The importance of thermal excitation and the resulting stability at remanence of the various metastable states observed is discussed. (C) 2004 American Institute of Physics.