Structural and magnetic transitions of embedded Fe and FePt nanoparticles
Funding: DFG grant PO1275/2-1
Collaboration: Prof. H. Lichte, TU Dresden
Abstract
The investigation of structural phase transitions of magnetic nanoparticles is recently intensely investigated. Especially if the particles are coherently embedded inside a host crystalline material, such transitions may show interesting properties. Even the stabilization of structural phases that usually would not exist in nature is possible. High resolution transmission electron microscopy and holography in combination with integral methods enables us to gain unique insight into the transitions on an atomic scale. The current project consists of two parts:
- Structural transitions from the fcc to the ferromagnetic bcc phase are investigated. The analysis is focused mainly on the magnetic properties of the exotic fcc phase.
- The transition from the disordered fcc phase to the ordered fct phase of embedded FePt nanoparticles is investigated. We focus on the influence of the host matrix on the
In addition, a simulation program based on the Preisach model was developed (PREM1.0) which allows interpretation of magnetometry data. It can be downloaded here.
Figures
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Embedded α-Fe nanoparticles in YSZ have been investigated by Transmission electron microscopy and holography
TEM |
TEH |
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| High resolutuion TeM allows the identification of the individual nanoparticle to be α-Fe. | TEH shows magnetic dipoles around individual nanoparticles (circles) |
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Simulations of zero field cooled and field cooled magnetization dependencies as well as hysteresis loops using the program PREM 1.0: The two magnetic systems exhibit equal hysteresis loops! The upper is fluctuation dominated, the lower anisotropy dominated.
Publications
Multiple ferromagnetic secondary phases in Fe implanted yttria stabilized zirconia
A. Shalimov, S. Q. Zhou, O. Roshchupkina, N. Jeutter, C. Baehtz, G. Talut, H. Reuther, K. Potzger
J. Appl. Phys. 108, 024907 (2010).
Fe nanoparticles embedded in MgO crystals
A. Shalimov, K. Potzger, D. Geiger, H. Lichte, G. Talut, A. Misiuk, H. Reuther, F. Stromberg, S. Q. Zhou, C. Baehtz, J. Fassbender
J. Appl. Phys. 105, 064906 (2009).
Memory effect of magnetic nanoparticle systems originating from particle size distribution
G. Zhang, K. Potzger, S. Q. Zhou, A. Muecklich, Y. C. Ma, and J. Fassbender
Nucl. Instrum. Meth. B 267, 1596 (2009).
Formation of metallic clusters in oxide insulators by means of ion beam mixing
G. Talut, K. Potzger, A. Muecklich, and Shengqiang Zhou
J. Appl. Phys. 103, 07D505 (2008).
Ion beam synthesis of Fe nanoparticles in MgO and yttria-stabilized zirconia
K. Potzger, H. Reuther, S. Q. Zhou, A. Mucklich, R. Grotzschel, F. Eichhorn, M. O. Liedke, J. Fassbender, H. Lichte, A. Lenk
