Elastic, magnetoelastic, magnetopiezoelectric, and magnetodielectric characteristics of HoAl3(BO3)(4)

The main elastic moduli and piezoelectric modulus have been measured in holmium alumoborate single crystals. The renormalization of the permittivity, piezoresponse, and sound velocities, driven by the nematic-like paramagnetic phase in the sample, is considered. A significant variability of the results is detected, which is caused, presumably, by the fact that, under the action of external fields, the motion trajectory of the nematic-like phase's director depends on random defects of thermoelastic origin. It is shown that above 5 K, the temperature dependences of the studied parameters are well-described using holmium ion's known ground multiplet spectrum, formed by the interaction with the crystal field. Changes in theC(44)-mode velocity in the sub-Kelvin temperature range are measured.