Magnetic and dielectric studies of multiferroic perovskite HoCr0.9TM0.1O3 (TM=Fe and Mn)

Two multiferroic perovskite systems - HoCr0.9Fe0.1O3 (HCFO) and HoCr0.9Mn0.1O3 (HCMO) have been prepared by the solid state ceramic method. Rietveld refinement of powder x-ray diffraction patterns of systems give the values of structural parameters and reveal that both the samples crystallize in orthorhombic symmetry. Magnetization measurements show the two samples exhibit two magnetic transitions-paramagnetic to canted antiferromagnetic (CAFM of Cr3+ sub-lattice) transition like HoCrO3 at similar to 140 K and corresponding to reorientation of Ho3+ spins at similar to 7 K. Sample HCMO shows an additional discontinuity (in M-T curve) at 35 K. Results are suggestive of the canting angle (in CAFM) to be larger in Mn substituted sample than in Fe substituted one, a reduced strength of AFM interaction in HCMO sample. Dielectric measurements have been made as a function of frequency and temperature. The samples show ferroelectric to paraelectric transitions at T-c similar to 515 K for HCFO and similar to 460 K for HCMO at an excitation frequency of 1 kHz.