Critical behaviour of the uniaxial dipolar ferromagnets LiTbF 4 and LiHoF 4: Effect of dilution by Y 3+

Abstract

We have measured the magnetic susceptibility χ of the pure and diluted uniaxial dipolar ferromagnets: LiHoF 4 ( T c = 1.530 K, LiTbF 4 ( T c = 2.891 K) and LiTb 0.5Y 0.5F 4 ( T c = 1.119 K. In contrast with pure compounds where the critical behaviour of χ is well fitted by the classical law with logarithmic corrections, a usual power law t −γ LiTb 0.5Y 0.5F 4.