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Extremely strong anisotropy of out-of-phase component of AC magnetic susceptibility in hematite single crystals and its origin
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SYSNO ASEP 0561314 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Článek ve WOS Název Extremely strong anisotropy of out-of-phase component of AC magnetic susceptibility in hematite single crystals and its origin Tvůrce(i) Hrouda, F. (CZ)
Ježek, J. (CZ)
Chadima, Martin (GLU-S) RID, SAIZdroj.dok. Studia geophysica et geodaetica. - : Geofyzikální ústav AV ČR, v. v. i. - ISSN 0039-3169
Roč. 66, 3-4 (2022), s. 187-205Poč.str. 19 s. Forma vydání Tištěná - P Jazyk dok. eng - angličtina Země vyd. CZ - Česká republika Klíč. slova out-of-phase susceptibility ; hematite ; single crystals Obor OECD Condensed matter physics (including formerly solid state physics, supercond.) Způsob publikování Omezený přístup Institucionální podpora GLU-S - RVO:67985831 UT WOS 000847600900001 EID SCOPUS 85137077572 DOI 10.1007/s11200-022-0829-2 Anotace So far unknown anisotropic properties of out-of-phase magnetic susceptibility (opMS) of hematite and their bearing on understanding the origin of hematite magnetism were investigated on example of four single crystals from Minas Gerais, Brazil. The research comprised measurement of directional variation of field-dependent and frequency-dependent opMS and testing whether the anisotropy of opMS can be represented by the second rank tensor. It was found that the opMS shows strong field dependence along basal plane and only weak field dependence along c-axis. As for the frequency dependence, it is virtually non-existent along the basal plane. Along the c-axis, the opMS is similar at frequencies 976 and 3904 Hz, while at 15616 Hz it is clearly higher. Consequently, opMS is dominantly due to weak field hysteresis. The minimum opMS directions are parallel to the c-axis, while the other two principal directions lie within basal plane. The degree of anisotropy is extremely high (ratio of maximum opMS to minimum opMS ≫100) and the anisotropy ellipsoid is very oblate. In stereographic diagrams, the opMS contours very roughly resemble the theoretical contours calculated from opMS tensor. However, the differences between measured and theoretical values in directional opMS are clearly higher than the measuring error and are distributed very non-homogeneously. This indicates that the second rank tensor is only very approximate representative of the spatial variation of the directional opMS of hematite single crystals. Earlier model of hematite magnetism assuming slightly scanted antiferromagnetism along the c-axis and strongly canted antiferromagnetism or even weak ferromagnetism along the basal plane is supported. Pracoviště Geologický ústav Kontakt Jana Popelková, popelkova@gli.cas.cz, Sabina Janíčková, Tel.: 233 087 272 Rok sběru 2023 Elektronická adresa https://link.springer.com/article/10.1007/s11200-022-0829-2
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