INVESTIGADORES
TROIANI Horacio Esteban
artículos
Título:
Magnetic propertiesofnanoscalecrystallinemaghemiteobtained by anewsyntheticroute
Autor/es:
MERCANTE; MELO; GRANADA; TROIANI; MACEDO; ARDISON; VAZ; NOVAK
Revista:
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2012 p. 3029 - 3033
ISSN:
0304-8853
Resumen:
In thisworkwedescribethesynthesisandcharacterizationofmaghemitenanoparticlesobtainedbyanewsyntheticroute.Thematerialwassynthesizedusingtriethylamineasacoprecipitationagentinthepresence oftheorganicligand N,N0-bis(3,5-di-tert-butyl-catechol)-2,4-diaminotoluene(LCH3). M¨ossbauerspectrum at4Kshowstypicalhyperfineparametersof maghemiteandTransmissionElectronMicroscopyimagesrevealthatthenanoparticleshaveameandiameterof3.9nmandanarrowsizedistribution.ACmagneticsusceptibilityinzerofieldpresentsanArrheniusbehaviorwithunreasonablerelaxationparametersduetothestronginfluenceofdipolarinteraction.Incontrastwhenthemeasurementsareperformed ina1kOefield,theeffectofdipolarinteractionsbecomesnegligibleandtheobtainedparametersareingoodagreementwiththestaticmagneticproperties.Thedynamicenergybarrierobtained fromtheACsusceptibilityresultsislargerthantheexpectedfromtheaveragesizeobservedbyHRTEMresults,evidencingthestronginfluenceofthesurfacecontributiontotheanisotropy.& 2012ElsevierB.V.Allrightsreserved
