Effect of strontium substitution on the structural and magnetic properties of La1.8Sr0.2MMnO6 (M = Ni, Co)-layered manganites

Karimunnesa, Syeda; Ahmmad, Bashir; Basith, M. A.

doi:10.1080/01411594.2016.1260723

Cited by 7 publications

(1 citation statement)

References 55 publications

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“…From the structural perspective, substituting Mn with an element having different ionic radii causes a change in the unit cell volume and lattice constants, eventually above a certain threshold the element substitution alters the crystal structure and affects its symmetry. This may lead to distortions in the crystal lattice, influencing the magnetic and transport properties of the manganite perovskites [16][17][18]. Moreover, there are reports that suggest modification at the Mn site with Nb, Ni or Fe ions could promote change in the crystal phases, such as rhombohedral, orthorhombic or cubic phases, and influence the transition temperatures between these phases [19,20].…”

Section: Introductionmentioning

confidence: 99%

Evidence of a Large Refrigerant Capacity in Nb-Modified La1.4Sr1.6Mn2−xNbxO7 (0.0 ≤ x ≤ 0.15) Layered Perovskites

Kumar,

Kim,

Sharma

et al. 2024

Magnetochemistry

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In this work, evidence of isothermal magnetic entropy change (∆SM) over a broad temperature region is presented in a series of La1.4Sr1.6Mn2−xNbxO7 Ruddlesden–Popper compounds with niobium modification (Nb) (0.0 ≤ x ≤ 0.15) at the manganese (Mn) site. The ceramic samples were obtained through a solid-state sintering method in optimized conditions. All compounds predominantly possessed Ruddlesden–Popper phase while a few additional reflections were resolved in Nb-doped compounds which indicates the separation of structural phases. These peaks are assigned to a separate layered perovskite and single perovskite with tetragonal symmetry and hexagonal symmetry, respectively. The microstructure of the pure sample reveals uniform grain morphology but in Nb-doped specimens chiefly three types of grains were found. It was assumed that the inter-connected large particles were of R-P phase which is dominant in both parent and x = 0.05 compounds, while the hexagonal and polygonal morphology of grains in higher concentrations of dopants directly corroborates with the symmetry of single perovskite and additional layered perovskite phases, respectively. The parent compound exhibits a single ∆SM curve, whereas all Nb-substituted samples display bifurcated ∆SM curves. This indicated two transition regions with multiple magnetic components, attributed to distinct structural phases. The highest ∆SM values obtained for components corresponding to the R-P phase are 2.32 Jkg−1k−1, 0.75 Jkg−1k−1, 0.58 Jkg−1k−1 and 0.43 Jkg−1k−1 and for the second component located around room temperature are 0.0 Jkg−1k−1, 0.2 Jkg−1k−1, 0.28 Jkg−1k−1 and 0.35 Jkg−1k−1 for x = 0.0, 0.05, 0.10 and 0.15 compositions, respectively, at 2.5 T. Due to the collective participation of both components the ∆SM was expanded through a broad temperature range upon Nb doping.

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