Abstract (EN):
This study provides a comprehensive insight into the effects of controlled off-stoichiometry on the structural and multiferroic properties of the hexagonal manganite LuMn1-xO3+delta (x = 0.02; delta similar to 0), supported by neutron powder diffraction measurements confirming single phase P6(3)cm symmetry and evidencing a relevant ferromagnetic component, below T-N similar to 90 K, which breaks the archetypal geometrically frustrated antiferromagnetic state typically ascribed to LuMnO3. The perturbations in the triangular disposition of spins prompt an additional electric polarization contribution and a clear enhancement of the magnetoelectric coupling which are in good agreement with the results of first principles calculations. In addition, Raman spectroscopy, dielectric permittivity, pyroelectric current and magnetic measurements as a function of temperature point out the precursor effects of the magnetic phase transitions involving a strong coupling between spins, lattice and electric order, even above the Neel temperature.
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
7