Giant magnetic coercivity and ionic superlattice nano-domains in Fe _0.25TaS₂

We have explored giant magnetic coercivity (H_c≈7 tesla) in the highly anisotropic ferromagnet of Fe_0.25TaS₂ through harnessing order of Fe²⁺ ions intercalated in-between TaS₂ layers. Fe ions order well in annealed crystals and form a (1/2,0,0) superlattice. However, a (1/3,1/3,0) superlattice, in addition to the (1/2,0,0) superlattice, can form in quenched crystals. These coexisting superlattices with nano-size domains result in significant change of magnetic domain configurations and huge enhancement of H_c, probably through efficient magnetic domain wall pinning by nano-size superlattice domains.