Nuclear Magnetic Relaxation in the Quasi-Two-Dimensional Heisenberg Paramagnet (C₁₈H₃₇NH₃)₂MnCl₄

Abstract

We have studied phase transitions and nuclear magnetic relaxation associated with phase transitions in the perovskite-type layered structure compound (C₁₈H₃₇NH₃)₂MnCl₄ by means of ¹H nuclear magnetic resonance (NMR). Spin–lattice relaxation was well described by the diffusion limited case, and a strong correlation between the NMR second moment and the spin–lattice relaxation rate, below a high phase transition temperature, provided a clue to its magnetic nature.