Giant magnetic coercivity and ionic superlattice nano-domains in Fe_0.25TaS₂

¹  Rutgers Center for Emergent Materials and Department of Physics & Astronomy - 136 Frelinghuysen Road, Piscataway, NJ, 08854, USA
²  Laboratory of Pohang Emergent Materials and Department of Physics, Pohang University of Science and Technology - Pohang 790-784, Korea
³  Research Department, NISSAN ARC, LTD. - Yokosuka, Kanagawa 237-0061, Japan

Received: 13 January 2009
Accepted: 20 April 2009

Abstract

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.