Magnetic properties of MnF3 investigated by 55Mn NMR and M(H) measurement

• The M(T) and M(H) curves of Manganese trifluorides were measured at low temperatures.
• The M(T) fits well to the magnetization of antiferromagnets with energy gap of 30 K.
• The relation of the anisotropy energy K with the exchange energy J is K=−1.8 J+9.8 .
• No evidence of the mixed magnetic phases were observed.

The M(T) and M(H) curves were measured to study the spin-ordered state in MnF3 at low temperatures. In order to obtain the temperature dependence of magnetization, Mn3+Mn3+ NMR resonance frequency was measured as a function of temperature. The resulting curve fits well to the initial temperature dependence of the magnetization expected for antiferromagnets with magnetic anisotropy, T3/2exp(−EG/kBT)T3/2exp(−EG/kBT), with an energy gap EG of about 30 K. From the comparison of the M(H) curve and classical theory, the relation between the anisotropy energy, Ka, and the exchange coupling constant between the nearest neighbors, J1, was found to be Ka∼−1.8J1+9.8Ka∼−1.8J1+9.8 in the absolute temperature unit.