Magnetostriction of Hexagonal HoMnO3 and YMnO3 Single Crystals

Abstract

We report on the magnetostriction of hexagonal HoMnO3 and YMnO3 single crystals in a wide range of applied magnetic fields (up to H = 14 T) at all possible combinations of the mutual orientations of magnetic field H and magnetostriction ΔL/L. The measured ΔL/L(H, T) data agree well with the magnetic phase diagram of the HoMnO3 single crystal reported previously by other authors. It is shown that the non- monotonic behavior of magnetostriction of the HoMnO3 crystal is caused by the Ho3+ ion; the magnetic moment of the Mn3+ ion parallel to the hexagonal crystal axis. The anomalies established from the magne- tostriction measurements of HoMnO3 are consistent with the phase diagram of these compounds. For the isostructural YMnO3 single crystal with a nonmagnetic rare-earth ion, the ΔL/L(H, T) dependences are described well by a conventional quadratic law in a wide temperature range (4–100 K). In addition, the mag- netostriction effect is qualitatively estimated with regard to the effect of the crystal electric field on the hol- mium ion.