title: Cobalt-Based Single-Ion Magnets on an Apatite Lattice: Toward Patterned Arrays for Magnetic Memories.
abstract: Single-ion magnets (SIMs) that can maintain magnetization direction on an individual transition metal atom represent the smallest atomic-scale units for future magnetic data storage devices and molecular electronics. Here we present a robust extended inorganic solid hosting efficient SIM centers, as an alternative to molecular SIM crystals. We show that unique dioxocobaltate(II) ions, confined in the channels of strontium hydroxyapatite, exhibit classical SIM features with a large energy barrier for magnetization reversal (Ueff) of 51-59 cm-1. The samples have been tuned such that a magnetization hysteresis opens below 8 K and Ueffincreases by a factor of 4 and can be further enhanced to the highest values among 3d metal complexes of 275 cm-1when Ba is substituted for Sr. The SIM properties are preserved without any tendency toward spin ordering up to a high Co concentration. At a maximal Co content, a hypothetical regular hexagonal grid of SIMs with a 1 nm interspacing on the (001) crystal facet would allow a maximal magnetic recording density of 105Gb/cm2.
authors.affiliation: Department of Chemistry, Moscow State University , 119991 Moscow, Russia.
authors.forename: Pavel E
authors.identifier: http://orcid.org/0000-0002-1415-2190
authors.initials: PE
authors.lastname: Kazin
authors.affiliation: Department of Materials Science, Moscow State University , 119991 Moscow, Russia.
authors.forename: Mikhail A
authors.initials: MA
authors.lastname: Zykin
authors.affiliation: Max Planck Institute for Chemical Physics of Solids , Nöthnitzer Strasse 40, 01187 Dresden, Germany.
authors.forename: Walter
authors.initials: W
authors.lastname: Schnelle
authors.affiliation: National Research Centre "Kurchatov Institute" , 123182 Moscow, Russia.
authors.forename: Yan V
authors.initials: YV
authors.lastname: Zubavichus
authors.affiliation: Department of Chemistry, Moscow State University , 119991 Moscow, Russia.
authors.forename: Konstantin A
authors.initials: KA
authors.lastname: Babeshkin
authors.affiliation: Department of Chemistry, Moscow State University , 119991 Moscow, Russia.
authors.forename: Victor A
authors.initials: VA
authors.lastname: Tafeenko
authors.affiliation: Max Planck Institute for Chemical Physics of Solids , Nöthnitzer Strasse 40, 01187 Dresden, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Felser
authors.affiliation: Max Planck Institute for Chemical Physics of Solids , Nöthnitzer Strasse 40, 01187 Dresden, Germany.|Max Planck Institute for Solid State Research , Heisenbergstrasse 1, 70569 Stuttgart, Germany.
authors.forename: Martin
authors.identifier: http://orcid.org/0000-0003-0762-0985
authors.initials: M
authors.lastname: Jansen