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Unusual magnetodielectric effects in La2CuMnO6 induced by a dynamic crossover in dielectric relaxation at TCJasnamol Pezhumkattil Palakkal,
Cheriyedath Raj Sankar,
Ajeesh Parayancheri Paulose,
Matjaž Valant,
Artem Badasyan,
Manoj Raama Varma, 2018, izvirni znanstveni članek
Opis: A series of fixed frequency dielectric measurements shows dielectric relaxation in La2CuMnO6, with a dynamic
(Arrhenius to Arrhenius) crossover at TC. The external magnetic field alters the relaxation parameters in the
vicinity of crossover and induces an unusual trend in the magnetodielectric coupling around TC. A large magnetodielectric
coupling of 55% (at 68 K, 4 kHz) and 61% (at 105 K, 285.8 kHz) under a small magnetic field of
5 kOe is discovered. Presence of ferromagnetic short-range correlations above TC and a sign reversal of magnetoresistance
around TC are observed. Specific heat analysis revealed the presence of ferromagnetic, variable
range hopping active charge localized state. The presence of ferromagnetic short-range correlations and the
influence of a core-grain dominated magnetoresistance on the Maxwell-Wagner interfacial polarization are responsible
for the observed large magnetodielectric effect. Both the magnetic ordering and external magnetic
field control the electric dipole relaxation in the material.
Ključne besede: Double perovskite
Griffiths-like phase
Dielectric
Magnetoresistance
Magnetodielectric
Objavljeno v RUNG: 03.01.2018; Ogledov: 4412; Prenosov: 0
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