Study of ferroelectric phase transition in Pb₅Ge₃O₁₁by paramagnetic resonance of Gd³⁺centres

Abstract

To cite this article: V.A. Vazhenin, E.L. Rumyantsev, M.Yu. Artyomov & A.P. Potapov (2015): Study of ferroelectric phase transition in Pb 5 Ge 3 O 11 by paramagnetic resonance of Gd 3+ centres, Phase Transitions,The temperature dependence of the fine structure of trigonal paramagnetic Gd 3C centres in Pb 5 Ge 3 O 11 was investigated in a wide temperature range in the vicinity of structural phase transition. The temperature dependence of the squared order parameter has been constructed based on the obtained data. It was shown that for the adequate description of its behaviour, the sixth-power term in polarization must be taken into account in the expansion of the thermodynamic potential. The orientational dependence of anomalous broadening of electron paramagnetic resonance signals in the vicinity of ferroelectric phase transition was studied. By comparison of the observed behaviour with the angular dependences of the line width that are characteristic of various broadening mechanisms, it was inferred that it can be attributed to defect induced statistical dispersion of fine structure triclinic parameters.