Data di Pubblicazione:
2009
Abstract:
WestudytheeffectofSbsubstitutionforPrinthehole-dopedsystemPr0.67Ba0.33MnO3 (PBMO)for
different dopinglevelsofSb.Thetwoelectricalresistivitytransitionsobservedinthepristinesample
PBMOshifttolowtemperaturesonSbdopingwithanoverallincreaseintheelectricalresistivity.The
significantlocallatticedistortionandthegrainboundaryeffectscausedbythelargecationsize
mismatchbetweenPr3+ and Sb3+ suppressesthedouble-exchange(DE)interactionandenhancesthe
super-exchange(SE)interaction.Thecompoundsshowasignificantandincreasingvalueof
magnetoresistanceattemperaturesbelowtheCurietemperature,notexpectedfromtheDEmodel.
The CurietemperaturedecreaseswithincreaseinSbcontentbutthesaturationmagnetizationislittle
affectedbythesubstitution.Thespins,however,staywellalignedinthelow-temperatureregime.Our
X-raynear-edgeabsorptionspectra(XANES)andcorelevelphotoemission(XPS)dataclearlyshowthe
Sb cationtobein+3stateandruleoutanypossibilityofe-dopinginourcompounds.
Tipologia CRIS:
01.01 Articolo in rivista
Keywords:
Manganite; SQUID; X-ray photoemission; XANES; Magnetoresistance
Elenco autori:
Carleschi, Emanuela; Parmigiani, Fulvio; Bondino, Federica; Magnano, Elena
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