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R D Gomez - One of the best experts on this subject based on the ideXlab platform.
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Microscopic Domain structures in unidirectional and isotropic exchange coupled nio nife bilayers
Journal of Magnetism and Magnetic Materials, 2003Co-Authors: D G Hwang, J K Kim, Sangsuk Lee, Hyun Cheol Koo, S H Chung, M Dreyer, S. W. Kim, R D GomezAbstract:The dependence on nickel oxide thickness in unidirectional and isotropic exchange-coupled NiO/NiFe bilayer films was investigated by magnetic force microscopy to better understand exchange biasing at Microscopic length scales. As the NiO thickness increased, the Domain structure of unidirectional biased films formed smaller and more complex in-plane Domains. By contrast, for the isotropically coupled films, large Domains generally formed with increasing NiO thickness including a new cross type Domain with out-of-plane magnetization orientation. The density of the cross Domain is proportional to exchange biasing field, and the fact that the Domain mainly originated from the strongest exchange coupled region was confirmed by imaging in an applied external field during a magnetization cycle.
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Microscopic Domain Structures in NiO Exchange - coupled Films
Journal of Magnetics, 2002Co-Authors: D G Hwang, J K Kim, Sangsuk Lee, M Dreyer, S. W. Kim, R D GomezAbstract:The dependence on nickel oxide thickness and a ferromagnetic layer thickness in unidirectional and isotropic exchange-coupled NiO/NiFe(Fe) bilayer films was investigated by magnetic force microscopy to better understand the relation between magnetic Domain structure and exchange biasing at Microscopic length scales. As the NiO thickness increased, the Domain structure of unidirectional biased films formed smaller and more complex in-plane Domains. By contrast, for the isotropically coupled films, large Domains generally formed with increasing NiO thickness including a cross type Domain with out-of plane magnetization orientation. The density of the cross Domain is proportional to exchange biasing field, and the fact that the Domain mainly originated from the strongest exchange coupled region was confirmed by imaging in an applied external field during a magnetization cycle.
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Microscopic Domain structure in unidirectional and isotropic exchange coupled nio nife bilayers
IEEE International Magnetics Conference, 2002Co-Authors: D G Hwang, J K Kim, Sangsuk Lee, Hyun Cheol Koo, S H Chung, M Dreyer, R D GomezAbstract:Summary form only given. The authors studied the thickness effect of NiO and NiFe on the Microscopic Domain structure and magnetization reversal in unidirectional and isotropic exchange-coupled NiO(0/spl sim/60 nm)/NiFe(5/spl sim/10 nm) films using magnetic force microscopy. As the NiO thickness increases, the Microscopic Domain structure of the unidirectional biased film changed from a mesh-type ripple pattern with no NiO to a more complicated and coarse-grained ripple structure at 60 nm. On the other hand, for the isotropic exchange coupled film, we observed a new cross-type Domain with out-of plane magnetization.
Yanjing Chen - One of the best experts on this subject based on the ideXlab platform.
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ore geology and fluid inclusion geochemistry of the tiemurt pb zn cu deposit altay xinjiang china a case study of orogenic type pb zn systems
Journal of Asian Earth Sciences, 2012Co-Authors: Yanjing ChenAbstract:Abstract The Tiemurt Pb–Zn–Cu deposit is hosted in a Devonian volcanic-sedimentary basin of the Altay orogenic belt, and is thus interpreted to have formed by sea-floor hydrothermal exhalation in previous studies. Our investigation discovered that the deposit is not stratiform or stratabound, but structure-controlled instead. The hydrothermal ore-forming process can be divided into the early, middle and late stage, represented by pyrite-quartz, polymetallic sulfide-quartz and carbonate-quartz veinlets, respectively. The early-stage veins and contained minerals are structurally deformed and brecciated, suggesting a compressional or transpressional tectonic regime. The middle-stage veinlets intrude and infill the fissures of the early-stage assemblages, and show no deformation, suggesting a tensional shear setting. The late-stage veinlets mostly infill open-space fissures that crosscut veins and replacements formed in the earlier stages. Four types of fluid inclusions (FIs), including aqueous (type W), carbonic-aqueous (type C), pure carbonic (type PC) and solid-bearing (type S), are identified at the Tiemurt deposit. The early-stage minerals contain the C- and W-type primary FIs that are totally homogenized at temperatures of 330–390 °C with low salinities of 0.8–11.9 wt.% NaCl eqv.; whilst the late-stage quartz or calcite contains only the W-type FIs with homogenization temperatures of 118–205 °C, and salinities of 1.4–3.4 wt.% NaCl eqv. This indicates that the ore fluid system evolved from CO2-rich, probably metamorphic to CO2-poor, meteoric fluids; and that a significant CO2-escape must have occurred. All the four types of FIs can be only observed in the middle-stage minerals, and even in a Microscopic Domain of a crystal, representing an association trapped from a boiling fluid system. These FIs homogenize at temperatures ranging from 270 to 330 °C, with two salinity clusters of 1.9–14.5 and 37.4–42.4 wt.% NaCl eqv., respectively. This implies that metal precipitation resulted from fluid boiling, CO2-escape and transient oversaturation. The estimated trapping pressures of FIs range from 130 to 380 MPa, suggesting an alternating lithostatic–hydrostatic fluid-system, controlled by a fault-valve at the depth of ∼13 km. Therefore, the Tiemurt Pb–Zn–Cu deposit is likely an example of orogenic Pb–Zn + Cu systems formed in collision orogeny, rather than a pre-collision VMS or Sedex system developed in Devonian; and a new metallogenic model is proposed to interpret the formation of the Tiemurt Pb–Zn–Cu deposit.
Chen Yanjing - One of the best experts on this subject based on the ideXlab platform.
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Ore geology and fluid inclusion geochemistry of the Tiemurt Pb-Zn-Cu deposit, Altay, Xinjiang, China: A case study of orogenic-type Pb-Zn systems
journal of asian earth sciences, 2012Co-Authors: Chen YanjingAbstract:The Tiemurt Pb-Zn-Cu deposit is hosted in a Devonian volcanic-sedimentary basin of the Altay orogenic belt, and is thus interpreted to have formed by sea-floor hydrothermal exhalation in previous studies. Our investigation discovered that the deposit is not stratiform or stratabound, but structure-controlled instead. The hydrothermal ore-forming process can be divided into the early, middle and late stage, represented by pyrite-quartz, polymetallic sulfide-quartz and carbonate-quartz veinlets, respectively. The early-stage veins and contained minerals are structurally deformed and brecciated, suggesting a compressional or transpressional tectonic regime. The middle-stage veinlets intrude and infill the fissures of the early-stage assemblages, and show no deformation, suggesting a tensional shear setting. The late-stage veinlets mostly infill open-space fissures that crosscut veins and replacements formed in the earlier stages. Four types of fluid inclusions (FIs), including aqueous (type W), carbonic-aqueous (type C), pure carbonic (type PC) and solid-bearing (type S), are identified at the Tiemurt deposit. The early-stage minerals contain the C- and W-type primary FIs that are totally homogenized at temperatures of 330-390 degrees C with low salinities of 0.8-11.9 wt.% NaCl eqv.; whilst the late-stage quartz or calcite contains only the W-type FIs with homogenization temperatures of 118-205 degrees C, and salinities of 1.4-3.4 wt.% NaCl eqv. This indicates that the ore fluid system evolved from CO2-rich, probably metamorphic to CO2-poor, meteoric fluids; and that a significant CO2-escape must have occurred. All the four types of FIs can be only observed in the middle-stage minerals, and even in a Microscopic Domain of a crystal, representing an association trapped from a boiling fluid system. These FIs homogenize at temperatures ranging from 270 to 330 degrees C, with two salinity clusters of 1.9-14.5 and 37.4-42.4 wt.% NaCl eqv., respectively. This implies that metal precipitation resulted from fluid boiling, CO2-escape and transient oversaturation. The estimated trapping pressures of FIs range from 130 to 380 MPa, suggesting an alternating lithostatic-hydrostatic fluid-system, controlled by a fault-valve at the depth of 13 km. Therefore, the Tiemurt Pb-Zn-Cu deposit is likely an example of orogenic Pb-Zn + Cu systems formed in collision orogeny, rather than a pre-collision VMS or Sedex system developed in Devonian; and a new metallogenic model is proposed to interpret the formation of the Tiemurt Pb-Zn-Cu deposit. (C) 2011 Elsevier Ltd. All rights reserved.Geosciences, MultidisciplinarySCI(E)0ARTICLE,SI69-794
D G Hwang - One of the best experts on this subject based on the ideXlab platform.
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Microscopic Domain structures in unidirectional and isotropic exchange coupled nio nife bilayers
Journal of Magnetism and Magnetic Materials, 2003Co-Authors: D G Hwang, J K Kim, Sangsuk Lee, Hyun Cheol Koo, S H Chung, M Dreyer, S. W. Kim, R D GomezAbstract:The dependence on nickel oxide thickness in unidirectional and isotropic exchange-coupled NiO/NiFe bilayer films was investigated by magnetic force microscopy to better understand exchange biasing at Microscopic length scales. As the NiO thickness increased, the Domain structure of unidirectional biased films formed smaller and more complex in-plane Domains. By contrast, for the isotropically coupled films, large Domains generally formed with increasing NiO thickness including a new cross type Domain with out-of-plane magnetization orientation. The density of the cross Domain is proportional to exchange biasing field, and the fact that the Domain mainly originated from the strongest exchange coupled region was confirmed by imaging in an applied external field during a magnetization cycle.
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Microscopic Domain Structures in NiO Exchange - coupled Films
Journal of Magnetics, 2002Co-Authors: D G Hwang, J K Kim, Sangsuk Lee, M Dreyer, S. W. Kim, R D GomezAbstract:The dependence on nickel oxide thickness and a ferromagnetic layer thickness in unidirectional and isotropic exchange-coupled NiO/NiFe(Fe) bilayer films was investigated by magnetic force microscopy to better understand the relation between magnetic Domain structure and exchange biasing at Microscopic length scales. As the NiO thickness increased, the Domain structure of unidirectional biased films formed smaller and more complex in-plane Domains. By contrast, for the isotropically coupled films, large Domains generally formed with increasing NiO thickness including a cross type Domain with out-of plane magnetization orientation. The density of the cross Domain is proportional to exchange biasing field, and the fact that the Domain mainly originated from the strongest exchange coupled region was confirmed by imaging in an applied external field during a magnetization cycle.
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Microscopic Domain structure in unidirectional and isotropic exchange coupled nio nife bilayers
IEEE International Magnetics Conference, 2002Co-Authors: D G Hwang, J K Kim, Sangsuk Lee, Hyun Cheol Koo, S H Chung, M Dreyer, R D GomezAbstract:Summary form only given. The authors studied the thickness effect of NiO and NiFe on the Microscopic Domain structure and magnetization reversal in unidirectional and isotropic exchange-coupled NiO(0/spl sim/60 nm)/NiFe(5/spl sim/10 nm) films using magnetic force microscopy. As the NiO thickness increases, the Microscopic Domain structure of the unidirectional biased film changed from a mesh-type ripple pattern with no NiO to a more complicated and coarse-grained ripple structure at 60 nm. On the other hand, for the isotropic exchange coupled film, we observed a new cross-type Domain with out-of plane magnetization.
M Dreyer - One of the best experts on this subject based on the ideXlab platform.
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Microscopic Domain structures in unidirectional and isotropic exchange coupled nio nife bilayers
Journal of Magnetism and Magnetic Materials, 2003Co-Authors: D G Hwang, J K Kim, Sangsuk Lee, Hyun Cheol Koo, S H Chung, M Dreyer, S. W. Kim, R D GomezAbstract:The dependence on nickel oxide thickness in unidirectional and isotropic exchange-coupled NiO/NiFe bilayer films was investigated by magnetic force microscopy to better understand exchange biasing at Microscopic length scales. As the NiO thickness increased, the Domain structure of unidirectional biased films formed smaller and more complex in-plane Domains. By contrast, for the isotropically coupled films, large Domains generally formed with increasing NiO thickness including a new cross type Domain with out-of-plane magnetization orientation. The density of the cross Domain is proportional to exchange biasing field, and the fact that the Domain mainly originated from the strongest exchange coupled region was confirmed by imaging in an applied external field during a magnetization cycle.
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Microscopic Domain Structures in NiO Exchange - coupled Films
Journal of Magnetics, 2002Co-Authors: D G Hwang, J K Kim, Sangsuk Lee, M Dreyer, S. W. Kim, R D GomezAbstract:The dependence on nickel oxide thickness and a ferromagnetic layer thickness in unidirectional and isotropic exchange-coupled NiO/NiFe(Fe) bilayer films was investigated by magnetic force microscopy to better understand the relation between magnetic Domain structure and exchange biasing at Microscopic length scales. As the NiO thickness increased, the Domain structure of unidirectional biased films formed smaller and more complex in-plane Domains. By contrast, for the isotropically coupled films, large Domains generally formed with increasing NiO thickness including a cross type Domain with out-of plane magnetization orientation. The density of the cross Domain is proportional to exchange biasing field, and the fact that the Domain mainly originated from the strongest exchange coupled region was confirmed by imaging in an applied external field during a magnetization cycle.
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Microscopic Domain structure in unidirectional and isotropic exchange coupled nio nife bilayers
IEEE International Magnetics Conference, 2002Co-Authors: D G Hwang, J K Kim, Sangsuk Lee, Hyun Cheol Koo, S H Chung, M Dreyer, R D GomezAbstract:Summary form only given. The authors studied the thickness effect of NiO and NiFe on the Microscopic Domain structure and magnetization reversal in unidirectional and isotropic exchange-coupled NiO(0/spl sim/60 nm)/NiFe(5/spl sim/10 nm) films using magnetic force microscopy. As the NiO thickness increases, the Microscopic Domain structure of the unidirectional biased film changed from a mesh-type ripple pattern with no NiO to a more complicated and coarse-grained ripple structure at 60 nm. On the other hand, for the isotropic exchange coupled film, we observed a new cross-type Domain with out-of plane magnetization.