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Dr Takeshi Kasama

Ph.D. (Univ. of Tokyo)

Department of Materials Science and Metallurgy
University of Cambridge
Pembroke Street
Cambridge CB2 3QZ

Office: HREM building room 802D
Tel: +44 1223 767066
Fax: +44 1223 334563
Email: tk305@cam.ac.uk
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Takeshi Kasama has been working on a project funded by the NERC (Natural Environment Research Council), entitled "How do magnetic interactions in nanoscale intergrowths affect palaeomagnetic interpretations?".

His Ph.D. (Apr. 1998 - Mar. 2001) was carried out in the Department of Earth and Planetary Science, University of Tokyo (Japan) and involved the interaction between minerals and microorganisms on the Earth's surface. After getting his degree he was employed as a postdoc at the Advanced Materials Laboratory, National Institute for Materials Science in Japan (Jul. 2001 - Nov. 2001) to develop new superior function materials for environmental purification. From Dec. 2001 to Jun. 2003 he worked as a postdoc at the Institute for Mineralogy, University of Muenster (Germany) and studied using high-resolution TEM, energy-filtered TEM, and Lorentz electron Microscopy on the relationships between magnetic properties and microstructure in minerals, especially in hematite-ilmenite series. From Jul. 2003 to Aug. 2006, he was a postdoc at the Quantum Phenomena Observation Technology Laboratory, RIKEN (The Institute of Physical and Chemical Research) in Japan and stayed at this group as a long-term vistor until Aug. 2006 to work on the development of electron holography for characterizing magnetic and electrostatic fields in nanostructured materials.

Takeshi Kasama's Research

1. Relationships between Microstructures and Magnetic Properties in Minerals

In order to understand the magnetic acquisition mechanisms and the magnetic properties of rocks in nature, most studies of rock magnetisms has been carried out by only bulk measurements, nevertheless it is necessary to examine relationships between microstructures and magnetic properties in rocks for essential understanding of rock magnetisms. Especially, we study about effects of microstructure on magnetic properties of magnetite [Fe3O4] and the origin of remanent magnetization in an exsolved hematite-ilmenite [Fe2O3-FeTiO3] system by combination of conventional TEM including energy-filtered TEM, off-axis electron holography and Lorentz electron microscopy.

2. Characterization of Magnetic and Electrostatic Properties in Nanomaterials

My research is to understand the magnetic and electrostatic structures of nanomaterials using off-axis electron holography and Lorentz electron Microscopy. These instruments are very powerful tools for investigating magnetic structures in materials with nanometers. Since the magnetic behavior of nanomaterials is strongly related to size, distribution, chemistry crystallographic orientation of the materials, we examine the correlations between the magnetic and electrostatic properties and microstructures including chemistry. We will investigate the electrostatic structures of biased semiconductors, transistors, and nanomaterials by using a TEM with the special sample holder that allow to observe them in-situ during supplying a bias voltage to the samples. These studies will contribute to develop the new technologies for magnetic storages and transistors.

Takeshi Kasama's Main Publications [2003-2006]

The latest publication list including papers submitted is here.

Kasama, T., Posfai, M., Chong, R.K.K., Finlayson, A.P., Buseck, P.R., Frankel, R.B., and Dunin-Borkowski, R.E.
Magnetic properties, microstructure, composition and morphology of greigite nanocrystals in magnetotactic bacteria from electron holography and tomography.
American Mineralogist 91, 1216-1229 (2006).

Kasama, T., Dunin-Borkowski, R.E., and Eerenstein, W.
Off-axis electron holography observation of magnetic microstructure in a magnetite (001) thin film containing anti-phase domains.
Physical Review B 73, 104432-1-7 (2006).

Kasama, T., Moreno, M.S., Dunin-Borkowski, R.E., Newcomb, S.B., Haberkorn, N., Guimpel, J., and Midgley, P.A.
Characterization of the magnetic properties of a GdBa2Cu3O7/La0.75Sr0.25MnO3 superlattice using off-axis electron holography.
Applied Surface Science 252, 3977-3983 (2006).

Harrison, R.J., Kasama, T., White, T.A., Simpson, E.T., and Dunin-Borkowski, R.E.
Origin of self-reversed thermoremanent magnetisation.
Physical Review Letters 95, 268501-1-3 (2005).

Kasama, T., Barpanda, P., Dunin-Borkowski, R.E., Newcomb, S.B., McCartney, M.R., Castano, F.J., and Ross, C.A.
Off-axis electron holography of pseudo-spin-valve thin film magnetic elements.
Journal of Applied Physics 98, 013903-1-7 (2005).

Kasama, T., McEnroe, S.A., Ozaki, N., Kogure, T., and Putnis, A.
Effects of nanoscale exsolution in hematite-ilmenite on the acquisition of stable natural remanent magnetization.
Earth and Planetary Science Letters 224, 461-475 (2004).

Kasama, T., Golla-Schindler, U., and Putnis, A.
High-resolution and energy-filtered TEM of the interface between hematite and ilmenite exsolution lamellae: Relevance to the origin of lamellar magnetism.
American Mineralogist 88, 1190-1196 (2003).

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