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Magnetic orders and origin of exchange bias in Co clusters embedded oxide nanocomposite films

Tijdschriftbijdrage - Tijdschriftartikel

Magnetic nanoparticles embedded oxide semiconductors are interesting candidates for spintronics in view of combining ferromagnetic (FM) and semiconducting properties. In this work, Co-ZnO and Co-V2O3 nanocomposite thin films are synthesized by Co ion implantation in crystalline thin films. Magnetic orders vary with the implantation fluence in Co-ZnO, where superparamagnetic (SPM) order appears in the low-fluence films (2  ×  1016 and 4  ×  1016 ions cm-2) and FM order co-exists with the SPM phase in high-fluence films (1  ×  1017 ions cm-2). Exchange bias (EB) appears in the high-fluence films, with an EB field of about 100 Oe at 2 K and a blocking temperature of around 100 K. On the other hand, Co-V2O3 thin films with an implantation fluence of 3.5  ×  1016 ions cm-2 exhibit a clear antiferromagnetic (AFM) coupling at low temperatures without the EB effect. The different magnetic behavior of the Co-implanted films with different Co content leads us to conclude that the observed EB effect in the Co-ZnO films results from the FM/AFM coupling between sizable Co nanoparticles and their CoO/Co3O4 surroundings in the (Zn,Co)O matrix. On the other hand, the absence of EB effect in Co-V2O3 appears to be due to the small size of the FM Co nanoparticles in spite of an AFM magnetic order. Detailed studies of magnetic orders and EB effect in magnetic nanocomposite semiconductors can pave the way for their application in spintronics.
Tijdschrift: Journal of Physics - Condensed Matter
ISSN: 0953-8984
Issue: 15
Volume: 31
Jaar van publicatie:2019
BOF-keylabel:ja
IOF-keylabel:ja
BOF-publication weight:1
CSS-citation score:2
Auteurs:International
Authors from:Higher Education
Toegankelijkheid:Closed