Modified crystal structure, dielectric and magnetic properties of Cr doped SmFeO3 ceramic
Abstract The effects of Cr3+ doping on the crystal structure, dielectric and magnetic phase transition of SmFeO3 have been investigated. The XRD pattern analysis shows that all the peaks for SmFe1-xCrxO3 samples can be indexed according to the crystal structure of pure SmFeO3 and has a fine crystal structure. The dielectric constants of SmFe1-xCrxO3 (x = 0.1–0.3) ceramics (er = 2532, 1959, 1172) are only 0.86, 0.67 and 0.41 times that of SmFeO3 (er = 2914) at 1 kHz, respectively. The change of dielectric constant (er) with x is mainly the result of the internal barrier layer capacitor (IBLC) mechanism and the dipole oriented polarization mechanism. It shows that the M-H of SmFeO3 at room temperature exhibits a butterfly shape disappears with the increase of Cr3+ and the magnetic properties is also gradually weakened, indicating that Cr3+ doping can effectively regulate the M-H of SmFeO3. On the M-T curve, it is found that the TSR and TN of SFO decrease from 462 K to 687 K–428 K and 536 K with increasing Cr3+, respectively. It is mainly because Cr3+ doping deforms the lattice structure of SmFeO3, destroys the antiferromagnetic order of Fe3+-O2--Fe3+ and forms the exchange interaction of Fe3+-O2--Cr3+. As a result of the three actions, the stability of the G-type antiferromagnetic structure of SmFeO3 is weakened, and the magnetic transition temperatures TSR and TN are decreased.