Incommensurate Jahn-Teller Phase Transitions in Tl2PbCu(NO2)6 and Rb2PbCu(NO2)6

In situ high-pressure single-crystal diffraction and spectroscopic techniques have been used to study a previously unreported Cu-framework bis[1-(4-pyridyl)butane-1,3-dione]copper(ii) (CuPyr-I).

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Jahn-Teller phase transitions; selection of the order parameter

Soviet Physics Journal ◽

10.1007/bf00896466 ◽

1989 ◽

Vol 32 (12) ◽

pp. 989-993

Author(s):

O. V. Gurin ◽

V. N. Syromyatnikov

Keyword(s):

Phase Transitions ◽

Order Parameter ◽

Jahn Teller ◽

Selection Of

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Dynamics of Jahn-Teller phase transitions

Ferroelectrics ◽

10.1080/00150197408237992 ◽

1974 ◽

Vol 7 (1) ◽

pp. 193-193 ◽

Cited By ~ 2

Author(s):

E. Pytte

Keyword(s):

Phase Transitions ◽

Jahn Teller

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Jahn-Teller Phase Transitions in Non-Stoichiometric Oxides with Perovskite Structure: Effect of Mechanical Activation

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.334-335.353 ◽

2013 ◽

Vol 334-335 ◽

pp. 353-358

Author(s):

Anatoly Yakovlevich Fishman ◽

Nickolai Tkachev

Keyword(s):

Phase Transitions ◽

Mechanical Activation ◽

Perovskite Structure ◽

Microscopic Description ◽

Oxide Systems ◽

Teller Transition ◽

Structure Phase ◽

Jahn Teller ◽

Nanostructural State ◽

Theoretical Results

Structure phase transitions in nonstoichiometry oxides with perovskite structure were considered. The microscopic description of cooperative Jahn-Teller transition was suggested and the effects caused by mechanical activation of oxide systems (their conversion into nanostructural state, acceleration of oxidation-renewal reactions and immiscibility) were analized. The correspondence of the theoretical results to the data of experiment on phase states of mechanically activated oxide NdMnO3is shown.

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Phase diagrams of Ni2+xMn1-xGa Heusler alloys from Hubbard Hamiltonian with account of Jahn-Teller effect

MRS Proceedings ◽

10.1557/opl.2011.633 ◽

2011 ◽

Vol 1310 ◽

Author(s):

Mikhail A. Zagrebin ◽

Vasiliy D. Buchelnikov ◽

Sergey V. Taskaev ◽

Natal’ya Yu. Fedulova

Keyword(s):

Phase Diagram ◽

Free Energy ◽

Phase Transitions ◽

Phase Diagrams ◽

Density Of States ◽

Heusler Alloys ◽

Teller Effect ◽

Hubbard Hamiltonian ◽

Jahn Teller ◽

Jahn Teller Effect

ABSTRACTIn this work a microscopic Hamiltonian is investigated using the Hubbard model for a ferromagnet with two degenerate bands, taking into account the Jahn-Teller effect. A macroscopic free energy is obtained from the microscopic Hubbard Hamiltonian. All free energy coefficients depend on microscopic parameters: temperature T and composition x. As a result of analytical minimization of free energy, phase diagrams are numerically constructed. It is shown that at certain values of parameters on the phase diagrams there are thermodynamic paths which correspond to experimentally observed sequences of phase transitions. Using density of states spectra for different compositions x the T-x phase diagram is numerically constructed. This phase diagram can theoretically explain experimentally observed behavior of the temperatures of phase transitions.

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