Dielectric and magnetic characteristics of Ca 1−x Mn x MoO 4 (0 ≤ x ≤ 0.15) nanomaterials

Abstract

Scheelite-type Ca_1−xMn_xMoO₄ (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 Ca_1−xMn_xMoO₄ (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.

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