Faraday effect aid birefringence in orthorhombic Li₂Ge₇O₁₅ near the ferroelectric phase transition

Abstract

The tensor of the Faraday effect and its temperature derivatives were determined from the temperature dependence of Faraday rotation and indices of refraction of orthorhombic Li ₂Ge₇O₁₅ between 120K and 340K, wave length 633nm. A strong anomaly of the Verdet constant V ₃₃ and of the index n ₃ was observed passing through the transition at 284K. The ratio of the slopes of the Verdet constant V ₃₃ above and below the transition is about -2. This value corresponds to a second-order ferroelectric phase transition.