arXiv subjects

Voicu Octavian Dolocan

Publications and source records attributed to Voicu Octavian Dolocan.

4 recordsLinked to original sources

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↗

arXiv2023

Magnetoelectric coupling in multiferroic CFO/BCTSn core shell nanofibers elaborated by co-axial electrospinning method

Multiferroic CoFe2O4-Ba0.95Ca0.05Ti0.89Sn0.11O3 core-shell nanofibers (CFO@BCTSn NFs) were synthesized by a sol-gel co-axial electrospinning technique. The scanning electron microscope and transmission electron microscope were used to check nanofibers' core-shell structure/configuration. X-ray diffraction and a high-resolution transmission electron microscope were used to confirm the spinel structure of CFO and the perovskite structure of BCTSn. The magnetic character of the resultant CFO@BCTSn NFs was determined by SQUID magnetometry. The piezoelectricity was verified using piezo-response force microscopy, which revealed an entirely covered ferroelectric shell outline, in accordance with SEM and TEM observations. The magnetoelectric (ME) coefficient was measured as a function of the applied external DC magnetic field. The maximum ME coefficient obtained for the CFO@BCTSn NFs was 346 mV cm-1 Oe-1. The high magnetoelectric coupling suggests that CFO@BCTSn NFs could be a promising candidate for magnetic field sensor and magnetoelectric device applications.

cond-mat.mtrl-sci↗

arXiv2014

On the Interaction between Fermions via Massless Bosons and Massive Particles

By using a Hamiltonian based on the coupling through flux lines, we have calculated the interaction energy between two fermions via massless bosons as well as via massive particles. In the case of interaction via massless bosons we obtain an equivalent expression for the Coulomb's energy on the form, where is the fine structure constant. In the case of the interaction via massive particles we obtain that the interaction energy contains a term building the potential well. Taking into account the spin-spin interaction of the nucleons, we show that this interaction modulates the interaction potential through a cosine factor. The obtained results are in good agreement with experimental data, for example, of deuteron.

nucl-th↗

arXiv2010

A model for semantic integration of business components

Today, reusable components are available in several repositories. These last are certainly conceived for the reusing However, this re-use is not immediate; it requires, in the fact, to pass through some essential conceptual operations, among them in particular, research, integration, adaptation, and composition. We are interested in the present work to the problem of semantic integration of heterogeneous Business Components. This problem is often put in syntactical terms, while the real stake is of semantic order. Our contribution concerns a model proposal for Business components integration as well as resolution method of semantic naming conflicts, met during the integration of Business Components.

cs.SE↗