Superparamagnetism in melt-spun CuCo granular samples

Hickey, B. J.; Howson, M. A.; Musa, S.O.; Tomka, G.J.; Rainford, B.D.; Wiser, Nathan

doi:10.1016/0304-8853(95)00068-2

Cited by 58 publications

(24 citation statements)

References 26 publications

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“…an applied magnetic field of 100 Oe for all three samples ( Fig. 2), show irreversibility, which is typical of the blocking process for an assembly of superparamagnetic nanoparticles [4]. T irr (the temperature below which irreversibility in ZFC and FC magnetization occurs) are found to be 150, 175 and B315 K for the samples with DE9; 10 and 11 nm; respectively.…”

Section: Methodsmentioning

confidence: 94%

Particle size-dependent magnetic properties of γ-Fe2O3 nanoparticles

Mukadam

Yusuf

Sharma

et al. 2004

Journal of Magnetism and Magnetic Materials

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Section: Methodsmentioning

confidence: 94%

Particle size-dependent magnetic properties of γ-Fe2O3 nanoparticles

Mukadam

Yusuf

Sharma

et al. 2004

Journal of Magnetism and Magnetic Materials

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“…This was shown 36,37 to lead to a linear dependence of the magnetoresistance on the SPM magnetization for high fields, i.e., MR͑H͒ ϰ L͑x͒. The above discussed results [36][37][38][39][40] refer to an extension of conventional granular alloys containing SPM particles only to the case when FM particles are also present. The aim of the present paper is to show that in some cases the conventional picture of magnetic/nonmagnetic multilayers with purely FM layers only should be extended in the opposite way, i.e., by accounting also for the presence of SPM regions.…”

Section: Introductionmentioning

confidence: 92%

Decomposition of the magnetoresistance of multilayers into ferromagnetic and superparamagnetic contributions

et al. 2004

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An analysis of both magnetic and magnetotransport properties is presented for electrodeposited multilayers prepared intentionally under conditions to make the superparamagnetic (SPM) magnetization contribution comparable to or larger than the ferromagnetic term. Based on a model elaborated for the giant magnetoresistance (GMR) of granular metals [N. Wiser, J. Magn. Magn. Mater. 159, 119 (1996); B. Hickey et al., Phys. Rev. B. 51, 667 (1995)], it is shown that in such multilayers both the magnetization and the GMR can be decomposed into ferromagnetric and superparamagnetic contributions where the latter term is described by a Langevin function. The size of the SPM regions estimated from the experimental data is in the nanoscale regime. It is believed that the method applied here gives a quantitative answer to the problem of the often observed nonsaturating behavior of GMR in multilayers. Electrodeposited multilayers are particularly prone to this feature although the occurrence of SPM regions is quite common in multilayers prepared by any technique. Therefore, this type of analysis should help better understanding of the factors influencing the GMR of multilayer films.

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“…However, besides this phenomenon, the granular structures containing nano-sized magnetic particles also provide a unique setting to investigate their basic properties, structural and magnetic, for example, such as kinetics of nucleation and growth as well as a diversity of magnetic phases which can exist in these structures and also magnetic interactions of different origin, and many others (see, e.g. [4,5]). The purpose of the present work thus was to carry out more extensive and detailed studies of the magnetic properties of nanogranular CoCu structures than those previously reported by the present authors (see, e.g.…”

Section: Introductionmentioning

confidence: 99%