Magnetic Properties of Systems of Low Dimensions

Abstract

The topic of low‐dimensional ferromagnetism is presented by means of examples: three specific systems illustrate phase transitions, domain patterns, and domain walls. Stripe‐domain phases and their transformations are described in ultrathin, perpendicularly magnetized Fe/Cu films, and related to two‐dimensional phase transitions. The domain patterns in small elements are discussed in stepped Co/Cu(001), an in‐plane‐magnetized system with tunable anisotropy. A wealth of different domain patterns is observed, exhibiting a distinct size and thickness dependence. A microscopic investigation of domain walls that are confined to small elements and pinned at constrictions is performed in Fe 20 Ni 80 . The wall types and profiles are found to deviate strongly from those encountered in extended films. A comparison with micromagnetic simulations leads to insight into the energetics driving these modifications.