Intrinsic dielectric properties of magnetodielectric La₂CoMnO₆

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Manganites with double perovskite structure are being attractive because of their interesting magnetoelectric and dielectric responses. Particularly, colossal dielectric constant (CDC) behavior has been observed in La₂CoMnO₆ (LCMO), at radio frequencies and room temperature. In this paper, we employed infrared-reflectivity spectroscopy onto a LCMO ceramic obtained through a modified Pechini's method to determine the phonon contribution to the intrinsic dielectric response of the system and to investigate the CDC origin. The analysis of the main polar modes and of the obtained phonon parameters show that CDC effect of LCMO is of pure extrinsic origin. In addition, we have estimated the dielectric constant and quality factor of the material in microwave region, e'ₛ 16 and Qᵤ × f 124 THz, which shows that LCMO is appropriate for applications into microwave devices and circuitry.