guest ::
| Home > Publications database > Size-dependent magnetic transitions in CoFe$_0.1$Cr$_1.9$O$_4$ nanoparticles studied by magnetic and neutron-polarization analysis |
| Home > Publications database > Size-dependent magnetic transitions in CoFe$_0.1$Cr$_1.9$O$_4$ nanoparticles studied by magnetic and neutron-polarization analysis |
| Journal Article | FZJ-2016-07342 |
; ; ; ; ;
2016
IOP Publ.
Bristol
This record in other databases: 
Please use a persistent id in citations: doi:10.1088/0957-4484/27/17/175702
Abstract: Multiferroic, CoCr2O4 bulk material undergoes successive magnetic transitions such as a paramagnetic to collinear and non-collinear ferrimagnetic state at the Curie temperature (T C) and spiral ordering temperature (T S) respectively and finally to a lock-in-transition temperature (T l). In this paper, the rich sequence of magnetic transitions in CoCr2O4 after mixing the octahedral site with 10% of iron are investigated by varying the size of the particle from 10 to 50 nm. With the increasing size, while the T C increases from 110 to 119 K which is higher than the T C (95 K) of pure CoCr2O4, the T S remains unaffected. In addition, a compensation of magnetization at 34 K and a lock-in transition at 10 K are also monitored in 50 nm particles. Further, we have examined the magnetic-ordering temperatures through neutron scattering using a polarized neutron beam along three orthogonal directions after separating the magnetic scattering from nuclear-coherent and spin-incoherent contributions. While a sharp long-range ferrimagnetic ordering down to 110 K and a short-range spiral ordering down to 50 K are obtained in 50 nm particles, in 10 nm particles, the para to ferrimagnetic transition is found to be continuous and spiral ordering is diffused in nature. Frequency-dependent ac susceptibility (χ) data fitted with different phenomenological models such as the Neel–Arrhenius, Vogel–Fulcher and power law, while ruling out the canonical spin-glass, cluster-glass and interacting superparamagnetism, reveal that both particles show spin-glass behavior with a higher relaxation time in 10 nm particles than in 50 nm. The smaller spin flip time in 50 nm particles confirms that spin dynamics does not slow down on approaching the glass transition temperature (T g).
Keyword(s): Magnetic Materials (1st) ; Condensed Matter Physics (2nd) ; Magnetism (2nd) ; Materials Science (2nd)
; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; National-Konsortium ; Nationallizenz
; No Authors Fulltext ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection
|
The record appears in these collections: |
PDF
PDF (PDFA)