Record details

    Low-temperature magnetism of alabandite: Crucial role of surface oxidation
    Čuda, J.
    Filip, J.
    Haloda, J.
    Kohout, Tomáš
    Kosterov, A.
    Medřík, I.
    Santala, E.
    Skála, Roman
    Tuček, J.
    Zbořil, R.
Publication type
    článek v odborném periodiku
Source title - serial
    American Mineralogist
    Roč. 98, 8/9
    s. 1550-1556
    Projekt: KJB300130903, GA AV ČR3cav_un_auth*0252840
    Rozsah: 7 s. : E
Subject category
    alabandite (MnS)
    experimental mineralogy
    ferromanganese deposit
    hausmannite (Mn3O4)
    low temperature
    magnetic anomaly
    magnetic field
    manganese deposit
    remanent magnetization
    troilite (FeS)
Abstract (in english)
   Manganese(II) monosulphide crystallizes into three different polymorphs (α-, β-, and γ-MnS). Out of these, α-MnS, also known as mineral alabandite, is considered the most stable and is widespread in terrestrial materials as well as in extraterrestrial objects such as meteorites. In this study, a low-temperature antiferromagnetic state of α-MnS was investigated using macroscopic magnetic measurements as induced and remanent field-cooled (FC) and zero-field-cooled (ZFC) magnetizations and magnetic hysteresis. Both natural alabandite and synthetic samples show: (1) Néel temperatures in a narrow temperature range around 153 K, and (2) a rapid increase of the magnetization around 40 K. An anomalous magnetic behavior taking place at about 40 K was previously ascribed to the magnetic transition from a high-temperature antiferromagnetic to a low-temperature ferromagnetic state documented for non-stoichiometric α-MnS slightly enriched in manganese.
   However, our detailed microscopic observations and, in particular, oxidation experiments indicate that the anomalous magnetic behavior around 40 K is caused by the presence of an oxide layer of ferrimagnetic hausmannite (Mn 3O4) on the surface of α-MnS rather than being an intrinsic property of nearly stoichiometric α-MnS.
    AV ČR Brno, Geologický ústav
Contributor code
    AV ČR, GLÚ
Source format
Import date
    23. 10. 2014