Dipole‐dipole interactions in KEr(MoO4)2 (abstract)

The model of a dipole‐dipole magnet previously developed1,2 has applied to a KEr(MoO4)2 crystal with two paramagnetic ions in an orthorhombic unit cell. The erbium ion in the compound has a large anisotropy of an effective g tensor which, in turn, leads to Ising‐like behavior in the magnetic subsystem. As had been done earlier,2 we had calculated the dipole configuration with the lowest energy, thus obtaining the ground‐state structure that would appear at the magnetic phase transition. This dipole structure consists of ferromagnetic chains aligned along the c axis and antiferromagnetically coupled along a and b axes. The results were compared with recently done measurements of magnetic moment and low‐temperature magnetic susceptibility.3 Calculated dipole ground energy E min=−1.325 K is in reasonable agreement with the experimental value of Tn=0.9 K. The obtained easy‐axis direction along the c axis also agreed with experiment. The phase transition observed in crystal at H∥c in our model results in a tra...