ISSN:
1572-9540
Keywords:
spin‐Peierls transition
;
superexchange interaction
;
symmetry
;
thermal contraction
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract The Fe‐doped system Cu0.9Ge0.9Fe0.2O3 has been investigated by means of X‐ray diffractometry, Mössbauer spectroscopy and superconducting quantum interference device. The structure of this system is orthorhombic and the lattice constants are a=4.784 Å, b=8.472 Å and c=2.904 Å, respectively. Magnetic measurements confirm that the spin‐Peierls transition appears in our sample at about 12 K, which is near to the spin‐Peierls transition temperature (T sp) 14 K of pure CuGeO3 system. The Mössbauer spectrum shows the superposition of two Zeeman sextets and a broad central line due to Fe3+ ions from room temperature to 4.2 K. The Mössbauer parameters show a discontinuity near T sp. The jump of the magnetic hyperfine field at temperatures lower than T sp means increasing of the superexchange interaction among the magnetic ions. The jump of the quadrupole splitting and the isomer shift values could be interpreted as due to decrement in symmetry of lattice sites and spontaneous thermal contraction.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1012634831485
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