title: Mn5Si3 Nanoparticles: Synthesis and Size-Induced Ferromagnetism.
abstract: Mn-based silicides are fascinating due to their exotic spin textures and unique crystal structures, but the low magnetic ordering temperatures and/or small magnetic moments of bulk alloys are major impediments to their use in practical applications. In sharp contrast to bulk Mn5Si3, which is paramagnetic at room temperature and exhibits low-temperature antiferromagnetic ordering, we show ferromagnetic ordering in Mn5Si3 nanoparticles with a high Curie temperature (Tc ≈ 590 K). The Mn5Si3 nanoparticles have an average size of 8.6 nm and also exhibit large saturation magnetic polarizations (Js = 10.1 kG at 300 K and 12.4 kG at 3 K) and appreciable magnetocrystalline anisotropy constants (K1 = 6.2 Mergs/cm(3) at 300 K and at 12.8 Mergs/cm(3) at 3 K). The drastic change of the magnetic ordering and properties in the nanoparticles are attributed to low-dimensional and quantum-confinement effects, evident from first-principle density-functional-theory calculations.
authors.forename: Bhaskar
authors.initials: B
authors.lastname: Das
authors.forename: Balamurugan
authors.initials: B
authors.lastname: Balasubramanian
authors.forename: Priyanka
authors.initials: P
authors.lastname: Manchanda
authors.forename: Pinaki
authors.initials: P
authors.lastname: Mukherjee
authors.forename: Ralph
authors.initials: R
authors.lastname: Skomski
authors.affiliation: Department of Physics and Astronomy, University of Delaware , Newark, Delaware 19716, United States.
authors.forename: George C
authors.initials: GC
authors.lastname: Hadjipanayis
authors.forename: David J
authors.initials: DJ
authors.lastname: Sellmyer
keywords: Mn-based alloys; Nanoparticles; ferromagnetism; quantum confinement