Effect of Preparation Conditions on Magnetic and Dielectric Properties of Y₂MMnO₆ (M = Co, Ni)

Abstract

Herein we report the structure, magnetic and dielectric properties of Y 2 CoMnO 6 (YCMO) and Y 2 NiMnO 6 (YNMO) prepared under various conditions. On annealing in inert atmosphere, YCMO sample shows a partial decomposition while YNMO remains unaffected. Both YCMO and YNMO samples show paramagnetic to ferromagnetic transition around 80 K, but only the magnetic properties of YCMO samples depend on the preparation conditions. YCMO samples show antiferromagnetic ground state in zero field and a metamagnetic transition at relatively low field (~2 T). Differences in the annealing environment do not destroy the initial antiparallel spin order in YCMO, but affect the critical fields of metamagnetic transition. The field-dependent magnetic properties indicated soft ferromagnetic nature of YNMO samples. The dielectric measurements show distinct frequency and temperature-dependent features in YCMO samples compared to YNMO samples. A large relative permittivity with e‫׳‬ of about 10 4 is observed in both O 2 and air-annealed YCMO samples. Multiple dielectric relaxations are observed in all the annealed YCMO and YNMO samples.

A brief review on the effect of preparation conditions on magnetic properties of some A2MMnO6 (A = La, Eu and Y; M = Mg, Co, Ni) type perovskites

“…The monoclinic distortions in the lattices are only feeble, viz., b * 89.8°. 20 However a partial intermixing of octahedral cations (about 24% in case of Y 2 NiMnO 6 and *10% in Y 2 CoMnO 6 ) is observed in these samples. Interestingly, the magnetic properties of these perovskites are least influenced by the oxygen partial pressure of annealing environment.…”

“…In the recent years, magnetic and dielectric properties of a number of A 2 MM 0 O 6 (where A = lanthanide ions and M and/ or M 0 = transition metal ion) type materials prepared under different oxygen partial pressures have been investigated, and the sensitivity of these properties to feeble oxygen defects are explained by us. [17][18][19][20] Such perovskite type materials have been investigated for long time in the interest of their unusual and tunable magnetic properties. 8,9,[21][22][23][24][25][26][27][28] As an example, perovskite type LaMnO 3 and LaNiO 3 respectively exhibit antiferromagnetic and paramagnetic properties, 27,28 while the cation ordered La 2 NiMnO 6 shows ferromagnetic properties.…”

“…The specific preparation details are reported earlier in the literatures. [17][18][19][20] As an example of typical procedure of gel combustion process, the preparation of La 2 CoMnO 6 is mentioned here. Initially clear nitrate solutions of metal ions were prepared by dissolving La 2 O 3 , MnCO 3 and CoCO 3 in nitric acid.…”

Structural, electrical and magnetic properties of Nd – A – CoO3 (A = Sr, Ca) Perovskite Powders by Mechanical Alloying

“…Dielectric relaxation of various perovskite type materials arises from conduction or dipolar origins 57 . Room temperature dielectric properties were carried out in the range of 100 Hz–1 MHz.…”

Dielectric and impedance spectroscopy of Nd2CoIrO6 double perovskite

“…Perovskite based compounds (ABO 3 ), double perovskite (A 2 B 2 O 6 ) and quadruple perovskite (A 4 B 4 O 12 ) exhibit different kinds of exclusive electric polarizability like large dielectric constant, ferroelectric and relaxor ferroelectric which have potential applications in capacitors, piezoelectric, resonator and transducers [1]. The observation of colossal dielectric constant (∼10 5 ) over a wide temperature range (100-600 K) in A-site disordered quadruple perovskite CaCu 3 Ti 4 O 12 (CCTO) has attracted much attention to researchers to investigate dielectric properties of perovskite oxides [2]. The microscopic origin of large dielectric constant in CCTO is Maxwell-Wagner (MW) type polarization in electrically heterogeneous microstructure consisting of different grain and grain boundary resistivities and capacitances [3,4].…”