Electron paramagnetic resonance of the incommensurate cooperative Jahn-Teller compound Tl2PbCu(NO2)6

Electron-paramagnetic-resonance experiments, in the temperature range 4.5<T<375 K, are reported for the cooperative Jahn-Teller compound Tl2PbCu(NO2)6 which exhibits both incommensurate and commensurate phase transitions. A theory is presented which provides a unified explanation for the resonance and the structural data, and correctly predicts the relative magnitudes of the incommensurate and the commensurate phase-transition temperatures. © 1985 The American Physical Society.