Interactions and switching field distributions of nanoscale magnetic elements

Magnetic nano-elements made from NiFe and Co have been investigated using magnetic imaging in the transmission electron microscope. Nano-elements like these have possible uses for in-plane patterned media or solid state memory. In both cases the elements will need to be patterned into closely spaced arrays and magnetostatic interactions between the elements will begin to become significant. Arrays must therefore be designed so that an element's interactions with its neighbors will be small compared to its coercivity. Arrays of NiFe elements 300 nm long, 50-100 nm wide, and 26 nm thick, were fabricated by electron beam lithography and lift-off patterning. Their switching behavior and the interactions between them were studied in detail. Magnetization sequences were recorded and hysteresis loops constructed. For rows of NiFe elements with the gap between elements the same as the element width or larger, the interactions turn out to be small, suggesting that denser arrays would be possible. (C) 2000 American Institute of Physics. [S0021-8979(00)37008-6].