| We present the electronic structure, magnetic and dielectric properties of Ti doped BiMn2O5 multiferroic materials. The x-ray diffraction (XRD) studies of BiMn2-xTixO5 (0 ≤ x ≤ 0.5) indicate no structural change up to x = 0.5, though the lattice parameters (a, c) increase with further increase of x. Dielectric constant and magnetization data show the evolution of new dielectric anomalies at ~ 120 K and weak magnetic feature at ~ 86 K with the Ti substitution compared to that of undoped one. However, Ti replacement vanishes the ferroelectric transition of BiMn2O5 at ~ 35 K, and gradually suppresses the antiferromagnetic (AFM) ordering at ~ 39 K. XRD and x-ray absorption spectroscopy (XAS) data of the doped samples show the polarization of Bi 6s2 lone pair electrons, accountable for the new dielectric anomalies, whereas new weak magnetic feature at ~ 86 K is attributed to strong spin-phonon coupling. XAS studies on O K-, Mn K-, L3,2-, and Ti L3,2- edges of BiMn2-xTixO5 samples along with the reference compounds have been performed and compared to bestow the exact chemical states of functioning ions. The Ti L- edge spectra clearly indicates the substitution of Ti4+ ions in all samples. XRD as well as XAS data and increase of net magnetic moment coherently indicate the replacement of Mn4+ by Ti4+. |
|