title: Exchange bias in bulk layered hydroxylammonium fluorocobaltate (NH₃OH)₂CoF₄.
abstract: The magnetic properties of layered hydroxylammonium fluorocobaltate (NH(3)OH)(2)CoF(4) were investigated by measuring its dc magnetic susceptibility in zero-field-cooled (ZFC) and field-cooled (FC) regimes, its frequency dependent ac susceptibility, its isothermal magnetization curves after ZFC and FC regimes, and its heat capacity. Effects of pressure and magnetic field on magnetic phase transitions were studied by susceptibility and heat capacity measurements, respectively. The system undergoes a magnetic phase transition from a paramagnetic state to a canted antiferromagnetic state exhibiting a weak ferromagnetic behavior at T(C) = 46.5 K and an antiferromagnetic transition at T(N) = 2.9 K. The most spectacular manifestation of the complex magnetic behavior in this system is a shift of the isothermal magnetization hysteresis loop in a temperature range below 20 K after the FC regime-an exchange bias phenomenon. We investigated the exchange bias as a function of the magnetic field during cooling and as a function of temperature. The observed exchange bias was attributed to the large exchange anisotropy which exists due to the quasi-2D structure of the layered (NH(3)OH)(2)CoF(4) material.
authors.affiliation: Institute of Mathematics, Physics and Mechanics, Jadranska 19, 1000 Ljubljana, Slovenia. zvonko.jaglicic@imfm.si
authors.forename: Z
authors.initials: Z
authors.lastname: Jagličić
authors.forename: M
authors.initials: M
authors.lastname: Zentková
authors.forename: M
authors.initials: M
authors.lastname: Mihalik
authors.forename: Z
authors.initials: Z
authors.lastname: Arnold
authors.forename: M
authors.initials: M
authors.lastname: Drofenik
authors.forename: M
authors.initials: M
authors.lastname: Kristl
authors.forename: B
authors.initials: B
authors.lastname: Dojer
authors.forename: M
authors.initials: M
authors.lastname: Kasunič
authors.forename: A
authors.initials: A
authors.lastname: Golobič
authors.forename: M
authors.initials: M
authors.lastname: Jagodič
mesh_terms: D000465:Algorithms; D016880:Anisotropy; D002627:Chemistry, Physical / Q000379:methods*; D003035:Cobalt / Q000737:chemistry*; D017611:Fluorine Compounds / Q000737:chemistry*; D006358:Hot Temperature; D060526:Magnetic Fields; D008280:Magnetics; D008968:Molecular Conformation; D044367:Phase Transition; D011312:Pressure; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013696:Temperature
chemical_list: D017611:Fluorine Compounds; D000644:Quaternary Ammonium Compounds; D003035:Cobalt