Professor Pedro Autreto

@article{Mahapatra2023,

title = {Paramagnetic two-dimensional silicon-oxide from natural silicates},

author = {Preeti Lata Mahapatra and Caique Campos de Oliveira and Gelu Costin and Suman Sarkar and Pedro A. S. Autreto and Chandra Sekhar Tiwary},

url = {https://iopscience.iop.org/article/10.1088/2053-1583/ad10b9/meta},

doi = {10.1088/2053-1583/ad10b9},

issn = {2053-1583},

year  = {2023},

date = {2023-12-12},

urldate = {2024-01-01},

journal = {2D Mater.},

volume = {11},

number = {1},

publisher = {IOP Publishing},

abstract = {Abstract

               Silicon dioxide’s potential for having magnetic properties is fascinating, as combining its electronic capabilities with magnetic response seems promising for spintronics. In this work, the mechanisms that drive the change from diamagnetic behavior in pure silicates like SiO2 to paramagnetic behavior in transition metal-doped silicates like Rhodonite silicate (CaMn3Mn(Si5O15)) are explored. This naturally occurring Rhodonite (R)-silicate was thinned down while retaining its magnetic properties by liquid-phase scalable exfoliation. Exfoliating R-silicate into the two-dimensional (2D) structure by LPE increases magnetic coercivity, and the internal resistance to demagnetization (ΔHc) up to ∼23.95 Oe compared to 7.08 Oe for its bulk phase. DFT spin-polarized calculations corroborate those findings and explain that the origin of the magnetic moment comes mainly from the Mn in the doped 2D silicate due to the asymmetrical components of the Mn d and Si p states in the valence band. This result is further illustrated by the spin component differential charge densities showing that Mn and Si atoms display a residual up spin charge. Rhodonite’s unusual magnetic behavior has considerable potential for spintronics, data storage, and sensing technologies. Understanding the complex relationships between the structural, magnetic, and electronic properties of silicates is essential for developing new materials and composites as well as for driving future research.},

keywords = {Condensed Matter Physics, General Chemistry, General Materials Science, Mechanical Engineering, Mechanics of Materials},

pubstate = {published},

tppubtype = {article}

}

@article{DeSousa2023,

title = {Boron nitride nanotube peapods at ultrasonic velocity impacts: a fully atomistic molecular dynamics investigation},

author = {J M De Sousa and L D Machado and C F Woellner and M Medina and Pedro A. S. Autreto and D S Galvão},

doi = {10.1088/1361-648x/acd50b},

issn = {1361-648X},

year  = {2023},

date = {2023-08-23},

urldate = {2023-08-23},

journal = {J. Phys.: Condens. Matter},

volume = {35},

number = {33},

publisher = {IOP Publishing},

abstract = {Abstract

               Boron nitride nanotube peapods (BNNT-peapod) are composed of linear chains of C60 molecules encapsulated inside BNNTs, they were first synthesized in 2003. In this work, we investigated the mechanical response and fracture dynamics of BNNT-peapods under ultrasonic velocity impacts (from 1 km s−1 up to 6 km s−1) against a solid target. We carried out fully atomistic reactive molecular dynamics simulations using a reactive force field. We have considered the case of horizontal and vertical shootings. Depending on the velocity values, we observed tube bending, tube fracture, and C60 ejection. Furthermore, the nanotube unzips for horizontal impacts at certain speeds, forming bi-layer nanoribbons ‘incrusted’ with C60 molecules. The methodology used here is applicable to other nanostructures. We hope it motivates other theoretical investigations on the behavior of nanostructures at ultrasonic velocity impacts and aid in interpreting future experimental results. It should be stressed that similar experiments and simulations were carried out on carbon nanotubes trying to obtain nanodiamonds. The present study expands these investigations to include BNNT.},

keywords = {Condensed Matter Physics, General Materials Science},

pubstate = {published},

tppubtype = {article}

}

@article{Oliveira2023b,

title = {Optimized 2D nanostructures for catalysis of hydrogen evolution reactions},

author = {Caique Campos de Oliveira and Pedro A. S. Autreto},

doi = {10.1557/s43580-023-00549-7},

issn = {2059-8521},

year  = {2023},

date = {2023-06-00},

urldate = {2023-06-00},

journal = {MRS Advances},

volume = {8},

number = {6},

pages = {307--310},

publisher = {Springer Science and Business Media LLC},

keywords = {Condensed Matter Physics, General Materials Science, Mechanical Engineering, Mechanics of Materials},

pubstate = {published},

tppubtype = {article}

}