Methods and main equipment

Basic methods:

Magnetic resonance techniques:
  - Electron Paramagnetic Resonance, EPR
  - Electron Nuclear Double Resonance, ENDOR
  - Nuclear Magnetic Resonance, NMR

Simultaneous EPR-optical
spectroscopy,

Spin-dependent phenomena

 

Multifrequency spectroscopy gives indispensable information

   

 
Electron Paramagnetic Resonance, EPR

The Electron Paramagnetic Resonance arises when an electron spin placed in
a magnetic field absorbs microwave quantum.
Energy levels and the energy of microwave quantum

 

The EPR signal
A behavior of the electron spin at low, resonance and high magnetic fields
   

 

 
Main advantages of
the EPR

 

 

 


Expected EPR spectra

The EPR data allow us to determine for paramagnetic impurity:
§  - kind and charge state of the impurity, §
  - symmetry of the lattice site, §
  - value of crystal field at this site...
 

 
Electron Nuclear Double Resonance, ENDOR

The ENDOR signal is the change of the EPR signal which appears
when a nuclear spin absorbs radiofrequency quantum.

Electron spin, microwave frequency (magenta).
Nuclear spin, radiofrequency (green).
Main advantages of
the ENDOR


Expected ENDOR spectra

The ENDOR data allow us to determine:
§  - surrounding, i.e. impurity location,
§  - position and sort of charge compensator,
§  - distortion around impurity,
§  - distribution of the wave function …
 

 

 

The EPR/ENDOR spectrometer
ELEXSYS 560.

The EPR with DICE ENDOR,
3cm and 8mm bands,
operated in
the temperature range
from 2 K to 300 K.

 

 

 

Expandable ELEXSYS
500-600 series
 from BRUKER

 

 

 The EPR spectrometer

Varian E-109

  

 
 

Optical Multi-channel Analyzer (OMA).

OMA  is available due to cooperation
with the group of  Prof. O.Schirmer
(Osnabrück University)