On the realization of artificial XY spin chains

Spin chains are the most elementary entities in the study of magnetic ordering behavior. The authors describe a route toward the realization of artificial XY spin chains. Using thin-film deposition and e-beam lithog., 300 and 550 nm diam. pillars consisting of alternating disks of permalloy and Al2O3 were made. Shape anisotropy forces the magnetization in plane, creating a chain of two-dimensional magnetic moments ->i. The disks couple to each other by their dipolar stray fields, resulting in an interaction Jij->i.->j, with Jij the coupling between disks i and j. This form closely resembles a chain of xy spins, coupled by effective interactions Jij. The authors present a magnetic characterization of the pillars, and compare the results with model calcns. Also, spin dynamics and ordering phenomena are addressed. [on SciFinder (R)]