Probing multiferroicity and spin-spin interactions via angular dependent dielectric measurements on Y-doped $HoMnO3$ in high magnetic fields

Dielectric measurements are used to characterize magnetic phase transitions in the doped ferroelectric oxides $Ho1−xYxMnO3$ $(x=0.4)$⁠. The focus of this experiment is on the effects of the magnetic field direction on the reentrant $T-B-θ$ phase diagram below the Néel temperature. The Ho sublattice plays a major role in all magnetic phase transitions for Y doping $(x=0.4)$⁠, consistent with previous results $(x=0,0.6,0.8)$⁠. Two successive Mn spin rotations in the $ab$ plane in the antiferromagnetic state are driven by the interaction with the Ho subsystem, although the Ho ordering peak in data is not pronounced. The dielectric response is a very sensitive probe for fine analysis of all aspects of spin-spin interactions in diluted $Ho1−xYxMnO3$⁠. The magnetic field anisotropy study is an important step towards the understanding of magnetic and electric phase competition in the diluted $4f$ system by the nonmagnetic yttrium (Y) ion.