Formation mechanism, optical and magneto-dielectric studies of new cubic spinel MgMnO 3

S. Thota (1, 2, 3) , K. Singh (1) , B. Prasad (3) , J. Kumar (3) , Ch. Simon (1) , Wilfrid Prellier (1)

1 CRISMAT - Laboratoire de cristallographie et sciences des matériaux
2 IIT Guwahati - Indian Institute of Technology Guwahati
3 IIT Kanpur - Indian Institute of Technology Kanpur

The formation mechanism, phase stability, optical and magnetodielectric properties of new cubic MgMnO3 bulk and nano-crystals are reported. The diffuse reflectance spectroscopy of this compound shows a ligand-to-metal charge transfer transition p[O2−]→eg[Mg2+] at 4 eV and the lowest spin allowed metal-to-metal transition at 2.43 eV. In bulk MgMnO3 with the defect cubic structure [Mg2+][Mg2+1/3Mn4+4/3□1/3]O4 (Seehra et al. Appl. Phys. Lett. 97, 112507 (2010)) a clear change in the dielectric constant (ɛ′) is observed on cooling through its blocking temperature TB ∼17.5 K. This dielectric anomaly is magnetic field independent even at 14 kOe. A clear evidence of the magneto-dielectric effect is observed for T < TB. Possible origin of the magneto-dielectric coupling has been discussed.

Mots clés: Optical properties; Dielectric properties; Absorption spectroscopy; Magnetic fields; Charge transfer; X-ray diffraction; Light diffraction; Reflectance spectroscopy; Nanocrystals; Magnetic ordering

Domaines: Matériaux; Chimie; Physique [physics]

S. Thota, K. Singh, B. Prasad, J. Kumar, Ch. Simon, et al.. Formation mechanism, optical and magneto-dielectric studies of new cubic spinel MgMnO 3. AIP Advances, 2012, 2 (3), pp.032140. ⟨10.1063/1.4747457⟩. ⟨hal-02118580⟩