Browsing NTNU Open by Author "Robinson, Peter"
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Chemical and magnetic properties of rapidly cooled metastable ferri-ilmenite solid solutions - IV: The fine structure of self-reversed thermoremanent magnetization
Robinson, Peter; McEnroe, Suzanne; Fabian, Karl; Harrison, Richard J.; Thomas, Christopher Ian; Mukai, Hiroshi (Journal article; Peer reviewed, 2014)Magnetic experiments, a Monte Carlo simulation and transmission electron microscopy observations combine to confirm variable chemical phase separation during quench and annealing of metastable ferri-ilmenite compositions, ... -
Chemical and magnetic properties of rapidly cooled metastable ferri-ilmenite solid solutions: II. Chemical changes during quenching and annealing
Robinson, Peter; Harrison, Richard J.; Miyajima, Nobuyoshi; McEnroe, Suzanne; Fabian, Karl (Journal article; Peer reviewed, 2012)Chemical and microstructural evolution during quench and short-term annealing of a sample XFeTiO3= 0.61 is explored in the light of observations in Paper I. Ordering proceeds by (1) random appearance of ordered and ... -
Chemical and magnetic properties of rapidly cooled metastable ferri-ilmenite solid solutions: implications for magnetic self-reversal and exchange bias - III. Magnetic interactions in samples produced by Fe-Ti ordering
Robinson, Peter; Harrison, Richard J.; Fabian, Karl; McEnroe, Suzanne (Journal article; Peer reviewed, 2012)Paper II of this series described the chemical and microstructural evolution of ferri-ilmenite solid solutions during high-T quench and short-term annealing. Here we explore consequences of these Fe–Ti ordering-induced ... -
Lamellar magnetism and exchange bias in billion-year-old metamorphic titanohematite with nanoscale ilmenite exsolution lamellae-III. Atomic-magnetic basis for experimental results
Robinson, Peter; McEnroe, Suzanne; Harrison, Richard John; Fabian, Karl; Heidelbach, Florian; Jackson, Michael (Peer reviewed; Journal article, 2021)Lamellar magnetism is a source of remanent magnetization in natural rocks different from common bulk magnetic moments in ferrimagnetic minerals. It has been found to be a source for a wide class of magnetic anomalies with ... -
Magnetic petrology of the Devonian Achala Batholith, Argentina: titanohaematite as an indicator of highly oxidized magma during crystallization and cooling
Geuna, S. E.; McEnroe, Suzanne; Robinson, Peter; Escosteguy, L.D. (Journal article; Peer reviewed, 2008)Devonian magmatism in the Eastern Sierras Pampeanas (Córdoba, Argentina) is represented by elliptical, porphyritic, batholithic, late- to post-orogenic monzogranites emplaced in a metamorphic—plutonic basement. Two groups ... -
Magnetic phases in hemo-ilmenite: Insight from low-velocity and high-field Mössbauer spectroscopy
Frandsen, C.; Mørup, S.; McEnroe, Suzanne; Robinson, Peter; Langenhorst, F. (Journal article; Peer reviewed, 2007)[1] We have studied natural samples of hemo‐ilmenite (ilmenite with hematite exsolution lamellae) by use of Mössbauer spectroscopy. The samples are from the Allard Lake intrusion in Quebec. The stoichiometric compositions ... -
Magnetic properties and potential field modeling of the Peculiar Knob metamorphosed iron formation, South Australia: An analog for the source of the intense Martian magnetic anomalies?
Schmidt, Phillip W.; McEnroe, Suzanne; Clark, David A.; Robinson, Peter (Journal article; Peer reviewed, 2007)[1] Magnetic property measurements show that the strongly metamorphosed Peculiar Knob iron formation (IF), South Australia, is coarse‐grained, high‐grade hematite with variable amounts of magnetite and maghemite. This body ... -
Magnetism at Depth: A View from an Ancient Continental Subduction and Collision Zone
McEnroe, Suzanne; Robinson, Peter; Church, Nathan Stewart; Purucker, Micheal (Journal article; Peer reviewed, 2018)Recent sophisticated global data compilations and magnetic surveys have been used to investigate the nature of magnetization in the lower crust and upper mantle. Two approaches to constraining magnetizations are developed, ... -
Magnetization of exsolution intergrowths of hematite and ilmenite: Mineral chemistry, phase relations, and magnetic properties of hemo-ilmenite ores with micron- to nanometer-scale lamellae from Allard Lake, Quebec
McEnroe, Suzanne; Robinson, Peter; Langenhorst, F.; Frandsen, Catherine; Terry, Michael P.; Ballaran, Tiziana (Journal article; Peer reviewed, 2007)[1] Hemo‐ilmenite ores from Allard Lake, Quebec, were first studied over 50 years ago. Interest was renewed in these coarsely exsolved oxides, based on the theory of lamellar magnetism as an explanation for the high and ... -
Spin orientation in solid solution hematite-ilmenite
Brok, Erik; Frandsen, Cathrine; Lefmann, Kim; McEnroe, Suzanne; Robinson, Peter; Burton, Benjamin P; Hansen, Thomas C; Harrison, Richard (Journal article; Peer reviewed, 2017)The spin orientation in synthetic hematite-ilmenite samples and in a sample of natural hematite was studied from room temperature to above the antiferromagnetic-paramagnetic phase transition (the Néel temperature; TN ≈ ...