Linear and Nonlinear Susceptibilities inCu97Co3Alloy for Ferromagnetic Fine Particles in Metallic Matrix: Comparison with Spin GlassAu96Fe4Alloy

Bitoh, Teruo; Ohba, Kazuyuki; Takamatsu, Masaki; Shirane, Takashi; Chikazawa, Susumu

doi:10.1143/jpsj.62.2583

Cited by 36 publications

(36 citation statements)

References 17 publications

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“…non-linear susceptibility was introduced as a direct probe for the divergence of Edwards-Anderson order parameter, signifying the onset of a spin-glass transition 25 . In a pioneering work, this issue has been taken up for Au 96 Fe 4 , known to be a spin-glass, and Co 97 Co 3 , which is a conventional superparamagnet 26 , while many such examples can consequently be drawn 27,28 .…”

Section: Resultsmentioning

confidence: 99%

Origin of the unconventional magnetoresistance in Sr ₂ FeMoO ₆

Ray

Middey

Jana

et al. 2011

EPL

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The unusual magnetoresistance (M R) behavior in Sr 2 FeMoO 6 , recently termed as spin-valve type MR (SVMR), presents several anomalies that are little understood so far. The difficulty in probing the origin of this phenomenon, arising from the magnetic property of only a small volume fraction of the ferromagnetic bulk, is circumvented in the present study by the use of ac susceptibility measurements that are sensitive to the slope rather than the magnitude of the magnetization. The present study unravels a spin-glass (SG) like surface layer around each soft ferromagnetic (FM) grain of Sr 2 FeMoO 6 . It is also observed that there is a very strong exchange coupling between the two, generating 'exchange bias' effect, which consequently creates the 'valve', responsible for the unusual M R effects.

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Section: Resultsmentioning

confidence: 99%

Origin of the unconventional magnetoresistance in Sr ₂ FeMoO ₆

Ray

Middey

Jana

et al. 2011

EPL

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“…1 An interesting subclass are the nanodispersions, that is, particulate assemblies dilutely supported in a matrix, either solid or liquid. To this group belong, for example, the magnetic colloids, 2 dilute granular alloys, 3 and some catalysts. 4 The size of the nanometric entities contained in those materials strongly affects their properties and, since the presence of very small clusters or even isolated atoms also play a role in some cases, the knowledge, as complete as possible, of the size distribution is a matter of prime interest in their characterization.…”

Section: Introductionmentioning

confidence: 99%

Superparamagnetic particles in ZSM-5–type ferrisilicates

et al. 1997

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As-synthesized, low iron content, ferrisilicates of ZSM-5-type contain well-separated Fe(III) ions in a tetrahedral environment and display paramagnetic behavior. After hydrothermal treatment, the iron ions are partially extracted from the framework, generating nanosize iron oxide or oxyhydroxide ferrimagnetic particles. This process has been studied by transmission electron microscopy (TEM), Mössbauer spectroscopy, magnetic ac susceptibility (x ac ), and field dependent magnetization, on samples containing up to 6.7 wt. % Fe. The experiments evidence the growth of nonaggregated particles, with a typical size around 3 nm, presumably located at the surface of the ferrisilicate crystallites. From a thorough granulometric analysis involving TEM and x ac data, it is concluded that, in the range from 1.5 to 4.6 wt. % Fe, the particle size distributions are significantly independent of the iron content.

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“…For instance, non-linear susceptibility was introduced as a direct probe for the divergence of Edwards-Anderson order parameter, signifying the onset of spin-glass transition [2]. Though in the past, there have been efforts to discern a spin glass phase from a superparamagnetic phase in conventional small particle systems using higher order susceptibility [4], there have been little effort for in-depth study in a vast variety of bulk magnetic materials including transition metal oxides, magnetic ceramics, metals etc., exhibiting signatures of metastability in bulk magnetization studies, the origin of which remains ambiguous.…”

Section: Linear and Non Linear Ac-χ As A Probe For Magnetic Systemsmentioning

confidence: 99%

“…This work explores the subtle differences in the nature of χ 3 to differentiate SPM from the SG phase , the details of which can be found in Ref. [4] and also in references therein.…”

Section: Probing Spin Glass and Superparamagnetic Systemsmentioning

confidence: 99%