On the exchange bias effect in NiO nanoparticles with a core(antiferromagnetic)/shell (spin glass) morphology

7th Meeting of the Spanish Neutron Scattering Association

Rinaldi-Montes, N.^1 ; Gorria, P.^1 ; Martínez-Blanco, D.^2 ; Fuertes, A.B.^3 ; Barquín, L Fernández^4 ; Fernández, J Rodríguez^4 ; De Pedro, I.^4 ; Fdez-Gubieda, M.L.^5 ; Alonso, J.^5 ; Olivi, L.^6 ; Aquilanti, G.^6 ; Puente-Orench, I.^7 ; Blanco, J.A.^1

Departamento de Física, Universidad de Oviedo, Oviedo

E-33007, Spain^1

Servicios Científico-Técnicos, Universidad de Oviedo, Oviedo

E-33006, Spain^2

Instituto Nacional Del Carbón, CSIC, Oviedo

E-33080, Spain^3

CITIMAC, Facultad de Ciencias, Universidad de Cantabria, Santander

E-39005, Spain^4

Univ. Basque Country, EHU, Dept. Elect. and Elect. and BCMaterials, Bilbao

E-48080, Spain^5

Sincrotrone Trieste S.C.p.A., S.S.14 Km 163.5, Basovizza, Trieste

34149, Italy^6

Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, Institut Laue-Langevin, BP 156, Grenoble Cedex 9

F-38042, France^7

关键词: Antiferromagnetic core;    Antiferromagnetics;    Core/shell;    Exchange bias effects;    Exchange coupled;    NiO nanoparticles;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/663/1/012001/pdf
DOI  :  10.1088/1742-6596/663/1/012001

来源: IOP

【 摘 要 】

The unexpected appearance of magnetic hysteresis and exchange bias effects in nominally antiferromagnetic NiO nanoparticles is usually explained in terms of a core/shell morphology, where a spin glass-like shell is exchange coupled to an antiferromagnetic core. However, recent studies have challenged the validity of this assumption for small enough NiO nanoparticles. In this work we present proof of the core/shell model for NiO nanoparticles with sizes below 10 nm by combining neutron powder diffraction and magnetic measurements. In addition, we have verified that the exchange bias effect persists even when the particle size is reduced down to 4 nm.