Today's interest in nanoparticle magnetism is stimulated by a variety of potential applications, ranging from soft to hard magnetic materials and from ultra-high density information storage to biomedical applications. Interactions between magnetic systems at the nanoscale give rise to novel effects, such as exchange bias (EB), enhancement in coercivity, spin-glass etc. A typical system where these types of interactions are present is ferromagnetic nanoparticles embedded in an antiferromagnetic matrix.This book describes the detail magnetic characterization of iron based nanocomposite materials synthesized by a chemical as well as high energy ball-milling techniques