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Magnetic nanostructures with application potential
Bittová, Barbara ; Kalbáčová Vejpravová, Jana (advisor) ; Holý, Václav (referee)
The thesis is mainly focused on the investigation of macroscopic and microscopic magnetic properties of selected nanomaterials containing cobalt and iron, and also the capability of our new device, scanning probe microscope Multimode V by Veeco, to directly visualise morphology and magnetic structure of these samples (Magnetic Force Miscroscopy, MFM). Investigated materials, such as CoFe2O4 nanoparticles and SiO2_Co_Si(111) thin films and multilayers are in general promising materials in many fields. In the medicine, the nanoparticles are used as the drug targets or contrast agents whereas in electronics, the (nano)granular thin films are the starting point in fabrication of high density storage media. The macroscopic magnetic properties of our samples are discusses in a view of superparamagnetic phenomena. The interactions in systems of nanoparticles are presented theoretically within the up-to date knowledge and also experimentally by demonstrating the behavior of the strongly-interacting, uper-spin-glass system. The thin films are studied in term of their granular structure and magnetic anisotropy. The morphology and the microscopic domain structure, respectively, are studied with use of the MFM. The first successful results obtained in our lab by this method are presented.
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Magnetic nanostructures with application potential
Bittová, Barbara ; Kalbáčová Vejpravová, Jana (advisor)
Title: Magnetic structures with application potential Author: Bc. Barbara Bittová Department: Department of condensed matter physics Supervisor: RNDr. Jana Poltierová Vejpravová Ph.D. Supervisor's e-mail address: jana@mag.cuni.cz Abstract: The thesis is mainly focused on the investigation of macroscopic and microscopic magnetic properties of selected nanomaterials containing cobalt and iron, and also the capability of our new device, scanning probe microscope Multimode V by Veeco, to directly visualise morphology and magnetic structure of these samples (Magnetic Force Miscroscopy, MFM). Investigated materials, such as CoFe2O4 nanoparticles and SiO2_Co_Si(111) thin films and multilayers are in general promising materials in many fields. In the medicine, the nanoparticles are used as the drug targets or contrast agents whereas in electronics, the (nano)granular thin films are the starting point in fabrication of high density storage media. The macroscopic magnetic properties of our samples are discusses in a view of superparamagnetic phenomena. The interactions in systems of nanoparticles are presented theoretically within the up-to date knowledge and also experimentally by demonstrating the behavior of the strongly-interacting, super-spin-glass system. The thin films are studied in term of their granular...
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Magnetic nanostructures with application potential
Bittová, Barbara ; Kalbáčová Vejpravová, Jana (advisor)
Title: Magnetic structures with application potential Author: Bc. Barbara Bittová Department: Department of condensed matter physics Supervisor: RNDr. Jana Poltierová Vejpravová Ph.D. Supervisor's e-mail address: jana@mag.cuni.cz Abstract: The thesis is mainly focused on the investigation of macroscopic and microscopic magnetic properties of selected nanomaterials containing cobalt and iron, and also the capability of our new device, scanning probe microscope Multimode V by Veeco, to directly visualise morphology and magnetic structure of these samples (Magnetic Force Miscroscopy, MFM). Investigated materials, such as CoFe2O4 nanoparticles and SiO2_Co_Si(111) thin films and multilayers are in general promising materials in many fields. In the medicine, the nanoparticles are used as the drug targets or contrast agents whereas in electronics, the (nano)granular thin films are the starting point in fabrication of high density storage media. The macroscopic magnetic properties of our samples are discusses in a view of superparamagnetic phenomena. The interactions in systems of nanoparticles are presented theoretically within the up-to date knowledge and also experimentally by demonstrating the behavior of the strongly-interacting, super-spin-glass system. The thin films are studied in term of their granular...
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Magnetic nanostructures with application potential
Bittová, Barbara ; Holý, Václav (referee) ; Kalbáčová Vejpravová, Jana (advisor)
The thesis is mainly focused on the investigation of macroscopic and microscopic magnetic properties of selected nanomaterials containing cobalt and iron, and also the capability of our new device, scanning probe microscope Multimode V by Veeco, to directly visualise morphology and magnetic structure of these samples (Magnetic Force Miscroscopy, MFM). Investigated materials, such as CoFe2O4 nanoparticles and SiO2_Co_Si(111) thin films and multilayers are in general promising materials in many fields. In the medicine, the nanoparticles are used as the drug targets or contrast agents whereas in electronics, the (nano)granular thin films are the starting point in fabrication of high density storage media. The macroscopic magnetic properties of our samples are discusses in a view of superparamagnetic phenomena. The interactions in systems of nanoparticles are presented theoretically within the up-to date knowledge and also experimentally by demonstrating the behavior of the strongly-interacting, uper-spin-glass system. The thin films are studied in term of their granular structure and magnetic anisotropy. The morphology and the microscopic domain structure, respectively, are studied with use of the MFM. The first successful results obtained in our lab by this method are presented.
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Magnetic properties of doped CeO.sub.2./sub. nanoparticles and CeO.sub.2./sub.-Fe.sub.2./sub.O.sub.3./sub. mixed oxides
Mantlíková, Alice ; Bittová, Barbara ; Burianová, Simona ; Vejpravová, Jana ; Nižňanský, D. ; Holec, Petr
We have investigated magnetic properties of CeO2 nanoparticles and CeO2/SiO2 nanocomposites doped by various magnetic metal oxide ions (Fe, Gd, Sm, Nd). Samples were obtained by co-precipitation and sol-gel method. Particle size has been obtained as 5 - 25 nm for nanocomposite and 25 - 100 nm for nanoparticles increasing with the increase of the annealing temperature. Detailed measurements of magnetization demonstrate paramagnetic state in the majority of the doped samples with maximum magnetization decreasing with the decrease of effective magnetic moment of the dopant ions from Gd3+ to Nd3+. It has been also observed, that the high-coercivity ε-Fe2O3 forms in CeO2-Fe2O3/SiO2 nanocomposite for higher concentration of the Fe ions (Ce/Fe/Si ratio equal to 1/2/9) and for the highest annealing temperature.
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