Investigation of low temperature magnetization, specific heat and magnetocaloric effect in Ho doped TbMnO3 multiferroic system

摘要

Ho doped TbMnO3 multiferroic manganites with the formula Tb1-xHoxMnO3 (where x = 0, 0.1 and 0.2) were synthesized through solid state reaction method. Structural characterization has been done using X-ray diffraction and results confirmed single phase nature of the samples. In order to determine the magnetic and ferroelectric transitions in the materials studied, heat capacity measurements have been undertaken at range 2-300 K for OT, 2T and 5T magnetic fields. From heat capacity studies three transitions were observed in all the samples in the temperature range 10-45 K. These transitions may be due to the ordering of Mn3+ ions and R3+ ions a detailed explanation of which is given below. Magnetocaloric effect has been studied from the heat capacity measurements under applied magnetic field. At 5T magnetic field, the samples exhibited a magnetic entropy change (Delta S)(M) of similar to 1.6 J/mol K and adiabatic temperature change (Delta T)(ad) of 3-4 K around 10K in the Ho doped TbMnO3 samples which is considerably high in comparison to earlier reports.