arXiv subjects

Afaak Lakouader

Publications and source records attributed to Afaak Lakouader.

3 recordsLinked to original sources

arXiv2025

BCZT/LSMO/BCZT multilayer films for high temperature energy storage capacitors

Ba0.85Ca0.15Zr0.1Ti0.9O3/La0.8Sr0.2MnO3/Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT/LSMO/BCZT) sandwich films were elaborated using the sol-gel spin coating process. The dielectric properties displayed excellent thermal stability with the temperature coefficient of capacitance, TCC, remaining within 10% between -50 C and 300 C. The high energy storage density, Wrec, of 11.8 J/cm3 observed in this sandwich films, is nearly twice as high as that of the BCZT films, with an efficiency, n, of 77% under a weak electric field of 800 kV/cm. Furthermore, the stability of Wrec and n was observed along the studied temperature interval making them promising candidates for high-temperature energy storage capacitors.

cond-mat.mtrl-sci↗

arXiv2024

Impact of Polymeric precursor and Auto-combustion on the Structural, Microstructural, Magnetic, and Magnetocaloric Properties of La0.8Sr0.2MnO3

In this work, La0.8Sr0.2MnO3 (LSMO) nanopowders are synthesized using two different methods: Pechini (LSMO-PC) and auto-combustion (LSMO-AC). Nanoparticle sizes, structural, magnetic, and magnetocaloric properties were determined and compared. The X-ray diffraction confirms the coexistence of two phases; rhombohedral symmetry with space group R-3c and orthorhombic symmetry with space group Pbnm, with the rhombohedral phase dominating. The scanning electron microscope images show that LSMO-PC has larger nanoparticle sizes (~495 nm) than LSMO-AC (~195 nm). The samples exhibit ferromagnetic properties with distinct hysteresis loops and Curie temperatures 340 K and 290 K for LSMO-PC and LSMO-AC respectively. The variation of the magnetic entropy was measured indirectly using the Maxwell approach with increasing magnetic field. For LSMO-PC it reaches a maximum -dSM=1.69 J/kg.K at 340 K and dH= 5 T. The associated adiabatic temperature change dTM is 1.04 K. While LSMO-PC demonstrates superior magnetic and magnetocaloric properties, LSMO-AC displays significant magnetocaloric thermal stability. The obtained values make LSMO-PC and LSMO-AC promising candidates for eco-friendly room-temperature magnetocaloric applications.

cond-mat.mtrl-sci↗

arXiv2022

Improved energy storage and electrocaloric properties of lead-free Ba0.85Ca0.15Zr0.1Ti0.9O3 ceramic

Lead-free ba0.85ca0.15zr0.1ti0.9o3 (bczt) ceramic powders were synthesized using the sol-gel method. to achieve high-energy storage and large electrocaloric effect in bulk ceramics the ceramics thickness was reduced. dielectric, ferroelectric, energy storage, and electrocaloric properties were investigated for bczt ceramic with 400 μm. here, pure crystalline structure and homogenous microstructure were identified by xrd analysis and sem measurements, respectively. the dielectric measurements revealed a maximum dielectric constant associated with ferroelectric-paraelectric phase transition. the maximum of ε was 7841 around 352 k. furthermore, the bczt ceramic showed improved energy storage and electrocaloric properties. a high recoverable energy density wrec of 0.24 j/cm3 and a total energy density wtotal of 0.27 j/cm3 with an efficiency coefficient of ~ 88% at 423 k under an electric field of 55 kv/cm was obtained. besides, the maximum value of δt = 2.32 k, the electrocaloric responsivity ζ = 0.42 k mm/kv, the refrigeration capacity rc= 4.59 j/kg and the coefficient of performance cop = 12.38 were achieved around 384 k under 55 kv/cm. the total energy density wtotal and the temperature change δt were also calculated by exploiting the landau-ginzburg-devonshire (lgd) theory. the theoretical results matched the experimental findings. these results suggest that the synthesized bczt ceramic with the reduced thickness could be a promising candidate for energy storage and electrocaloric applications.

cond-mat.mtrl-sci↗