Ti-doped YMnO3: Magnetic and thermal studies at low temperature and dielectric properties at high temperature

We study the magnetic, thermal, and dielectric properties in Ti-doped YMnO3. Crystal structure analysis showed that as Mn3+ is replaced by Ti4+ ions, a phase transition from hexagonal symmetry with P63cm space group to rhombohedral symmetry with R3c space group takes place at around x = 0.14 of Ti4+ doping. The local deformation, as well as the partial charge compatibility of the Ti+4 ion at the Mn+3,+4 site, allows solubility up to 20% in the YMnO3 matrix. The magnetic analysis at a low temperature showed that the effective moments, μeff, and the Curie-Weiss temperature, ƟCW, drop rapidly as Ti+4 replaces the Mn+3 ion. This fact indicates that the Mn3+ magnetic moments in the geometrically frustrated antiferromagnetic array are strongly decoupled by the Ti+4 substitution. Also, the magnetic contribution of the specific heat showed that the magnetic transition observed at about 75 K for the pristine sample decreases down to ∼40 K with increasing Ti+4 up to x = 0.20, which indicates that the frustrated (he...