Zobrazeno 1 - 10
of 93
pro vyhledávání: '"Massa, Néstor"'
Publikováno v:
Physical Review B 108, 115116 (2023)
We report on zone center THz excitations of non-Jahn Teller LaFeO$_3$, PrFeO$_3$, ErFeO$_3$, and LuFeO$_3$ distorted perovskites under external magnetic fields up 7 T. Low temperature-low energy absorptions of LaFeO$_3$ show antiferromagnetic and fer
Externí odkaz:
http://arxiv.org/abs/2303.02786
Autor:
Massa, Néstor E., del Campo, Leire, Holldack, Karsten, Canizarès, Aurélien, Phuoc, Vinh Ta, Kayser, Paula, Alonso, José Antonio
Publikováno v:
Phys. Rev. B 102, 134305 (2020)
We report the temperature dependent THz to mid-infrared response of hexagonal-ErMnO3 using absorption, reflectivity, and emissivity techniques from 2 K to 1700 K. At low temperatures, lowest frequency vibrational modes coexist with paramagnon excitat
Externí odkaz:
http://arxiv.org/abs/2010.06341
Autor:
Massa, Néstor E., del Campo, Leire, Holldack, Karsten, Phuoc, Vinh Ta, Echegut, Patrick, Kayser, Paula, Alonso, José Antonio
Publikováno v:
Phys. Rev. B 98, 184302 (2018)
We report on the high-temperature evolution of far- and mid- infrared reflectivity and emissivity spectra of ambient orthorhombic ErMnO3 from 12 K to sample decomposition above 1800 K. At low temperatures the number of phonons agrees with the predict
Externí odkaz:
http://arxiv.org/abs/1811.04694
Autor:
Massa, Néstor E., Holldack, Karsten, Sopracase, Rodolphe, Phuoc, Vinh Ta, del Campo, Leire, Echegut, Patrick, Alonso, José Antonio
We report on THz absorption spectroscopy combined with high magnetic fields of polycrystalline RCrO3 (R= Pr, Sm, Er) aiming understanding spin wave resonances at their low temperature magnetic phases. Our measurements show that the temperature, and t
Externí odkaz:
http://arxiv.org/abs/1708.01497
Autor:
Massa, Néstor E., Ramos, Aline Y., Tolentino, Helio C. N., Sousa-Neto, Narcizo M., Fonseca Jr., Jairo, Alonso, José Antonio
We report on XANES and EXAFS measurements of SmNiO3 from 20 K to 600 K and up to 38 GPa at the Ni K- and Sm L3- edges. A multiple component pre- Ni K-edge tail is understood originating from 1s transitions to 3d-4p states while a post-edge shoulder i
Externí odkaz:
http://arxiv.org/abs/1512.03011
Autor:
Massa, Néstor E., del Campo, Leire, Meneses, Domingos De Sousa, Echegut, Patrick, Martínez-Lope, María Jesús, Alonso, José Antonio
Publikováno v:
J. Phys. Condens. Matter 26 (2014) 275901
We report on TmMnO3 far infrared emissivity and reflectivity spectra from 1910 K to 4 K. At the highest temperature the number of infrared bands is lower than that predicted for centrosymmetric P63/mmc (D6h4) (Z=2) space group due high temperature an
Externí odkaz:
http://arxiv.org/abs/1406.4382
Autor:
Massa, Néstor E., del Campo, Leire, Meneses, Domingos De Sousa, Echegut, Patrick, Martínez-Lope, María Jesús, Alonso, José Antonio
Publikováno v:
J. Phys.: Condens. Matter 25 (2013) 235603
We report on near normal far- and mid-infrared emission and reflectivity of NdMnO3 perovskite from room temperature to sample decomposition above 1800 K. At 300 K the number infrared active phonons is in close agreement with the 25 calculated for the
Externí odkaz:
http://arxiv.org/abs/1309.1482
Autor:
Massa, Néstor E., García-Flores, Ali F., Meneses, Domingos De Sousa, del Campo, Leire, Echegut, Patrick, Fabbris, Gilberto F. L., Martínez-Lope, María Jesús, Alonso, José Antonio
We report on electronic collective excitations in RMn2O5 (R= Pr, Sm, Gd, Tb) showing condensation starting at and below TN\simTC\sim40-50 K. Its origin is understood as partial delocalized eg electron orbitals in the Jahn-Teller distortion of the pyr
Externí odkaz:
http://arxiv.org/abs/1204.3406
Autor:
Massa, Néstor E., del Campo, Leire, Meneses, Domingos De Sousa, Echegut, Patrick, Fabbris, Gilberto F. L., Azevedo, G. de M., Martínez-Lope, María Jesús, Alonso, José Antonio
Publikováno v:
JOURNAL OF APPLIED PHYSICS 108, 1 (2010)
We report on the lattice evolution of BiFeO3 as function of temperature using far infrared emissivity, reflectivity, and X-ray absorption local structure. A power law fit to the lowest frequency soft phonon in the magnetic ordered phase yields an exp
Externí odkaz:
http://arxiv.org/abs/1009.1773
Autor:
Massa, Nestor E., Denardin, Juliano C., Socolovsky, Leandro M., Knobel, Marcelo, Zhang, XiXiang
Publikováno v:
JOURNAL OF APPLIED PHYSICS 105, 114306 (2009)
We report on near normal infrared reflectivity spectra of ~550 nm thick films made of cosputtered transition metal nanograins and SiO2 in a wide range of metal fractions. Co0.85(SiO2)0.15,with conductivity well above the percolation threshold has a f
Externí odkaz:
http://arxiv.org/abs/0906.1805