| Magnetic Resonance and Dielectric Studies of a Nonlinear La 3 Ga 5.5 Ta 0.5 O 14 Single Crystal Doped with Erbium |
| T. Bodziony a , J. Typek a , M. Orlowski a , J. Majszczyk a , M. Wabia a , M. Berkowski b , W. Ryba-Romanowski c , N. Guskos d , V. Likodimos d and E.A. Anagnostakis d a Institute of Physics, Technical University of Szczecin, al. Piastów 17, 70-310 Szczecin, Poland b Institute of Physics, Polish Academy of Sciences, Warsaw, Poland c Institute of Low Temperature and Structure Research Polish Academy of Sciences, Wroc³aw, Poland d Solid State Section, Department of Physics University of Athens, Athens, Greece |
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| Single crystal of erbium doped La 3 Ga 5.5 Ta 0.5 O 14 grown by the Czochralski method have been investigated by electron paramagnetic resonance and dielectric spectroscopy methods. Dielectric permittivity ϵ measurements performed in 90--440 K temperature range have shown negligible dispersion for 1 kHz -- 1 MHz frequencies and a Curie--Weiss type behaviour with C=47700 K and θ=-340 K. Electron paramagnetic resonance studies have revealed the presence of two different paramagnetic, monoclinic centres. The calculated g factor values are: g 1 =1.449, g 2 =11.534, g 3 =4.24 for the main M 1 centre and g 1 =1.982, g 2 =4.169, g 3 =4.25 for the weaker M 2 centre. The temperature dependence of EPR line intensity for centre M 1 and M 2 is quite different --- while lines attributed to M 1 could only be observed at low temperatures, below 20 K, lines of M 2 centre persisted up to 200 K. The M 1 centre is connected with Er 3+ ion entering substitutionally into La 3+ site, while M 2 is probably connected with 3d ions at the same site, unintentionally introduced into the material as an admixture. |
| DOI: 10.12693/APhysPolA.103.315 PACS numbers: 76.30.Kg, 77.22.Ch |