Dielectric and magnetic characteristics of Ca1- x Mn x MoO4 (0 ≤ x ≤ 0.15) nanomaterials

J Nanopart Res. 2019;21(1):8. doi: 10.1007/s11051-018-4450-9. Epub 2018 Dec 31.

Abstract

Scheelite-type Ca1-x Mn x MoO4 (x = 0.0, 0.01, 0.05, 0.10 and 0.15) nanomaterials were successfully synthesized via a combustion route. Dielectric studies showed a weak n-type electrical conductivity characteristic for insulators and low relative permittivity (ε r < 15) decreasing with increasing Mn2+ content. CaMoO4 and Mn2+-doped nanomaterials are chemically compatible with Al and Ag electrodes and promising for low-temperature co-fired ceramic applications. Magnetic studies showed, at room-temperature diamagnetism for pure CaMoO4, the balance between diamagnetism and paramagnetism for Ca1-x Mn x MoO4 (x = 0.01) and paramagnetic behaviour when 0.05 ≤ x ≤ 0.15 as well as the short-range antiferromagnetic interactions growing in strength as Mn2+ content increases. The Landé factor fitting procedure showed a spin-only contribution to the magnetic moment. CaMoO4 matrix unexpectedly revealed the residual paramagnetism at low temperatures derived probably from the molybdenum ions having unpaired 4d electrons as well as a paramagnetic-diamagnetic transition at 70 K.

Keywords: Combustion synthesis; Electrical properties; Magnetic properties; Mn2+-doped nanomaterials; Scheelite-type structure.