Exploring Effects of Magnetic Nanowire Arrangements and Imperfections on First-Order Reversal Curve Diagrams

The first-order reversal curve (FORC) method is one of the most appealing magnetic characterization methods that has been used over decades for detailed analyses of nanoscaled magnetic systems. These detailed analyses are accompanied by numerous magnetic features in FORC diagrams that usually are difficult to explain fully. Here, the FORC diagrams of several magnetic nanowire (MNW) arrays are modeled and discussed. The focus is on how the MNW arrangement (i.e., hexagonal, random, and square) and imperfections (i.e., variation of coercivity,
$H_{c}$
) effects interaction fields (
$H_{u}$
) between MNWs, as well as switching events and FORC diagram features.
$H_{u}$
in hexagonal arrangements is higher than those in square or random arrangements because hexagonal is a close-packed arrangement, so there are more nearest neighbors. Furthermore, the FORC diagrams features were dictated not only by the
$H_{u}$
and
$H_{c}$
values but also by their standard deviation ratios (
$\sigma _{u}/\sigma _{c})$
, where “Wish-bone” features were observed for
$\sigma _{u}/\sigma _{c} \le 1$
and “T-shape” features were observed for
$\sigma _{u}/\sigma _{c} \ge 5$
.