EnglishThis work relates the crystal chemistry and the magnetic behaviour of a trioctahedral mica (chemical formula: K0.90Na0.01Ca0.01Ba0.01&0.07)(Al0.05Fe2+ 1.20Mg1.38Ti0.32Mn0.01&0.04)(Al1.12Si2.88)O10 (F0.27OH1.27O0.46); unit cell parameters: a = 5.345(2), b = 9.261(4), c = 20.189(8) A; b =95.075(8)º) from Minto Block (Ungava peninsula, northern Quebec, Canada), a region characterized by high magnetic anomalies. Crystallographic and X-ray absorption spectroscopy data suggest a prevalentdivalent oxidation state for Fe and a disordered Fe2+ distribution in the two octahedralsites M1 and M2. The realpart of magnetic susceptibility shows two peaks at ~5.2 K and 120 K. However, asdemonstrated by AC magnetic susceptibility measurements, the origin of the two effects is different: the peak position of the first one (i.e. the effect revealed at 5.2 K) is frequency-dependent, thus suggesting a spin-glass like behaviour. The effect at 120 K can instead be attributed to the occurrence of diluted phases in mica matrix, such as Fe oxides.
| Data di pubblicazione: | 2008 |
| Titolo: | Magnetic behaviour of trioctahedral mica-2M1 occurring in amagnetic anomaly zone |
| Autore/i: | S. PINI; M. AFFRONTE; MF BRIGATTI |
| Autore/i UNIMORE: | |
| Digital Object Identifier (DOI): | 10.1180/minmag.2008.072.5.1035 |
| Rivista: | |
| Volume: | 72 |
| Pagina iniziale: | 1035 |
| Pagina finale: | 1042 |
| Codice identificativo ISI: | WOS:000265132100004 |
| Codice identificativo Scopus: | 2-s2.0-64549135467 |
| Citazione: | Magnetic behaviour of trioctahedral mica-2M1 occurring in amagnetic anomaly zone / S. PINI; M. AFFRONTE; MF BRIGATTI. - In: MINERALOGICAL MAGAZINE. - ISSN 0026-461X. - STAMPA. - 72(2008), pp. 1035-1042. |
| Tipologia | Articolo su rivista |
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