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Temperature Dependence of Raman Scattering by Magnons in Bulk-Like MBE-Gwn MnTe Films

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Szuszkiewicz W., Mohrange J., Jouanne M., Kanehisa M., Świrkowicz R., Dynowska E., Janik E., Wojtowicz T., Kossut J.

Acta Physica Polonica A

1997

vol. 92

issue 5

1025-1028

Temperature dependence of the magnon frequency was studied for cubic MnTe epilayers by the Raman scattering measurements. Experimental data are compared to the results of theoretical calculations performed within the framework of the Heisenberg model using Green's function formalism.

Low-Frequency Raman Spectrum οf Bulk Zn_{0.984}Co_{0.016}O Crystal

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Szuszkiewicz W., Łusakowski A., Morhange J., Gołacki Z., Arciszewska M., Brodowska B., Kanehisa M., Klepka M., Dobrowolski W.

Acta Physica Polonica A

2009

vol. 116

issue 1

103-106

The influence of possible presence of Co^{2+} ion pairs in a bulk Zn_{1-x}Co_{x}O mixed crystal on the low-frequency part of the Raman spectrum is discussed. Two effects can be taken into account in the theoretical considerations when analyzing the energy level scheme corresponding to Co ions. The first is a local lattice deformation in the vicinity of Co^{2+} ion due to a presence of the second ion, smaller than the host ZnO lattice cation. Such deformation creates a trigonal field, which can only slightly modify the energy levels of Co^{2+} ion. The second effect, which results from an antiferromagnetic superexchange interaction between two Co^{2+} ions is responsible for a new set of energy levels. The Raman data taken at low temperature on the sample corresponding to the composition x = 0.016 demonstrated the presence of two structures at about 6 cm^{-1} and 13 cm^{-1}. These structures may be interpreted as electronic transitions between the ground state and the first excited state of a single Co^{2+} ion in the substitution site of ZnO lattice and as a similar transition for Co^{2+} ion pair, respectively.

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2 Acta Physica Polonica A

1 2009

1 1997

2 Kanehisa M.

2 Szuszkiewicz W.

1 Arciszewska M.

1 Brodowska B.

1 Dobrowolski W.

1 Dynowska E.

1 Gołacki Z.

1 Janik E.

1 Jouanne M.

1 Klepka M.

1 Kossut J.

1 Mohrange J.

1 Morhange J.

1 Wojtowicz T.

1 Łusakowski A.

1 Świrkowicz R.

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Temperature Dependence of Raman Scattering by Magnons in Bulk-Like MBE-Gwn MnTe Films

Low-Frequency Raman Spectrum οf Bulk Zn_{0.984}Co_{0.016}O Crystal