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Your search keyword '"Meneghini, Carlo"' showing total 18 results
Start Over Author "Meneghini, Carlo" Journal physical review b
18 results on '"Meneghini, Carlo"'

3. Short-range magnetic correlation, metamagnetism, and coincident dielectric anomaly in Na5Co15.5Te6O36

Author

Meneghini, Carlo, ITOH, MITSURU, Siruguri, Vasudeva, and Ray, Sugata

Abstract

Here we explore the structural, magnetic, and dielectric properties of Na5Co15.5Te6O36, which reveal development of a short-range magnetic correlation and a dielectric anomaly in the system above Nèel temperature (TN=) of 50 K. Low-temperature neutron powder diffraction (NPD) without any external magnetic field clearly indicates that the canted spin structure is responsible for the antiferromagnetic transition, and this canted spin structure brings several short-range ferromagnetic and antiferromagnetic correlations, and partially occupied Co form short-range magnetic correlation with other Co. Interestingly, a structural change in terms of changes in the lattice parameters and consequent development of dielectric anomaly around similar temperature is also recorded in the system. Additionally, the isothermal remanent magnetization and electron-spin resonance measurements reveal the presence of short-range magnetic correlations which coincide with an anomaly in the dielectric constant vs temperature curve. Further, a sharp jump in the magnetic-field-dependent magnetization clearly indicates the presence of metamagnetic transition, and magnetic-field-dependent NPD confirms that rotations of Co spins with applied magnetic field are responsible for this metamagnetic phase transition. Consequently, a magnetocaloric effect is developed in the system, which is suitable for the application in low-temperature refrigeration.

Published
2023

18. Cationic order versus La-O covalency in La A(Ca,Ba) VMoO6 double perovskites.

Author

Bandyopadhyay, Abhisek, Neogi, Swarup Kumar, Paul, Atanu, Meneghini, Carlo, Dasgupta, Indra, Bandyopadhyay, Sudipta, and Ray, Sugata

Subjects
*MAGNETIC properties of perovskite, *AB initio quantum chemistry methods, *PHASE separation
Abstract

We have investigated the structural and physical properties of double perovskite (DP) LaAVMoO6 (A = Ca2+, Ba2+; abbreviated as LCVMO and LBVMO from now on) compounds, proposed to be possible half-metallic antiferromagnets (HMAFMs). Here we show that within LaAVMoO6 double perovskite structure, La-O covalency competes against B-site as well A-site cationic order and this competition critically influences their physical properties. Evidently, the presence of Ca2+ or Ba2+ at the A site along with La3+ would offer a tool to modify the A-site ordering and consequently influence the La-O covalency as well. Our experimental results reveal that LCVMO lies at the extreme end of this family and accommodates large scale phase separation in terms of La, V, and Ca, Mo-rich phases as a result of dominant La-O covalency. On the other hand, LBVMO is more correctly described as a layered A-site ordered and nearly complete B-site disordered double perovskite where cationic order dominates the La-O covalency. The general trend of our experimental findings is in agreement with the ab initio electronic structure calculations, carried out on realistic structures based on local coordination obtained from extended x-ray-absorption fine-structure study. [ABSTRACT FROM AUTHOR]

Published
2017
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