Departmental Seminar

Radioactive Isotopes in nuclear solid state physics

Dr Patrick Kessler
National Metrology Institute of Germany

The method of the perturbed angular correlation is a well known method to measure electric field gradients (EFG) in solids. The first results were obtained in the 1970s where neutron activated metals were investigated. Since then many applications of this method have been established.

The present talk focuses on two examples in solid state physics: the measurement of point defects and internal magnetic fields in semiconductors. For this, the radioactive isotopes 117Cd, 111mCd and 100Pd are incorporated into the semiconductors AlN and ZnO. This is done via ion implantation, where implantation defects and annealing conditions can be studied. Afterwards, the lattice location of the implanted radioactive probe atoms is investigated with Rutherford backscattering channeling measurements. When this is established the samples are measured at low or elevated temperatures to study the long term temperature stability of the probe environments.

The expected EFG of the probe atoms in these crystals can be calculated with DFT methods and can be compared to the obtained PAC results.

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