Magnetic Phase Diagrams of Hexagonal RMnO$_{3}$ (R = Ho, Tm, Er)

The magnetic phase transitions in the phase diagrams of RMnO$_{3}$ (R = Er, Tm, Ho) are correlated to changes in their dielectric properties proving the existence of strong spin-lattice coupling in these compounds. For the case when R = Tm and Er, their N\'{e}el phase transition line decreases slightly with increasing external magnetic fields up to 7 Tesla and at low temperatures a phase transition line is detected at higher external fields which possibly merges with the N\'{e}el phase transition line at fields above 7 Tesla. For the case when R = Ho, a far more complex phase diagram was discovered including spin reorientation phase transitions and additional previously unknown phases with magnetic structures of which have yet to be explored.