Memory in nanomagnetic systems: Superparamagnetism versus spin-glass behavior

Bandyopadhyay, Malay; Dattagupta, Sushanta

doi:10.1103/physrevb.74.214410

Cited by 124 publications

(102 citation statements)

References 36 publications

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“…5,12,32,33 To investigate their influence on the FC memory effect, LSMO nanoparticles have been diluted by mixing them with icing sugar with a 1.3/30.6 mg weight ratio. Then, the second protocol has been employed on the LSMO/icing sugar mixture with different waiting times of 0.1, 0.2, 0.3, 1, and 2 h at 50 K. The measured magnetization during the different waiting periods is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Measurements such as frequency-dependent AC magnetic susceptibility, field cooled (FC) and zero-field cooled (ZFC) magnetization as a function of temperature, and time-dependent magnetization to investigate aging, memory effects, and non-exponential relaxation are used to study the slow dynamical properties of superparamagnetic and spin glass systems. 5,[9][10][11][12][14][15][16] The La 1-x Sr x MnO 3 perovskite manganites are some of the most captivating magnetic materials due to their colossal magnetoresistance, half-metallicity, and magnetocaloric and optical properties. 4,17,18 Among these manganites, La 1-x Sr x MnO 3 with x ¼ 0.33 has the highest Curie temperature of 380 K. 18 Single-domain magnetic nanoparticles with large saturation magnetization and a Curie temperature above room temperature have potential for use in hyperthermia, MRI contrast enhancement, and drug delivery applications.…”

Section: Introductionmentioning

confidence: 99%

“…[5][6][7][8][9] While non-interacting superspins show superparamagnetic behavior, strong interparticle interactions can lead to a superspin glass state in a dense ensemble of magnetic nanoparticles. [5][6][7][9][10][11][12][13] Collective freezing of the superspins can be studied by various static and dynamic magnetic techniques. Measurements such as frequency-dependent AC magnetic susceptibility, field cooled (FC) and zero-field cooled (ZFC) magnetization as a function of temperature, and time-dependent magnetization to investigate aging, memory effects, and non-exponential relaxation are used to study the slow dynamical properties of superparamagnetic and spin glass systems.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic properties, exchange bias, and memory effects in core-shell superparamagnetic nanoparticles of La0.67Sr0.33MnO3

Rostamnejadi

Venkatesan

Salamati

et al. 2017

Journal of Applied Physics

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The static magnetic properties and memory and exchange bias effects have been studied in sol-gel prepared La 0.67 Sr 0.33 MnO 3 (LSMO) nanoparticles. Transmission electron microscopy (TEM) micrographs and static magnetization show log-normal particle and magnetic size distributions with a core-shell structure. Analysis of the magnetization measurements indicates the presence of a magnetic structure with a 7.8 nm core radius and a magnetic dead layer of thickness 1.6 nm in the LSMO nanoparticles, which comprises about 40% of the volume. The disordered spins in the shell freeze at lower temperatures than the core and produce a surface spin glass state exhibiting a weak exchange bias effect. Field cooled and zero-field cooled magnetization measurements have been carried out to study the slow dynamics of the sample and associated magnetic memory effects; the results reveal the superparamagnetic behavior of LSMO nanoparticles described in terms of the magnetic size distribution rather than a superspin glass state. Published by AIP Publishing.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Magnetic properties, exchange bias, and memory effects in core-shell superparamagnetic nanoparticles of La0.67Sr0.33MnO3

Rostamnejadi

Venkatesan

Salamati

et al. 2017

Journal of Applied Physics

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“…Nanoparticles that are dispersed within a matrix can show some very interesting magnetic properties that are related to interactions between the moments on each particle. Competing interactions and changes in particle size can cause a system to show superparamagnetic, super spin glass or super ferromagnetic properties [11,12,13].…”

Section: Introductionmentioning

confidence: 99%

Controlling nickel nanoparticle size in an organic/metal–organic matrix through the use of different solvents

2013

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(2013) 'Controlling nickel nanoparticle size in an organic/metal-organic matrix through the use of di erent solvents. ', Nanoscale., 5 (24). pp. 12212-12223. Further information on publisher's website:http://dx.doi.org/10.1039/c3nr04883gPublisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. (0) atoms from the Ni(COD)2. Materials are characterised with a combination of X-ray diffraction, electron microscopy and magnetometry and it is found that samples made using a halocarbon solvent resulted in clustered bulk Ni particles (size ≤ 10 nm) with anomalously high superparamagnetic blocking temperatures. Using an isocyanide solvent produces smaller (size ∼ 1 nm), well dispersed particles that show little evidence of superparamagnetic blocking in the range of temperatures investigated (> 2 K). In all samples there is another component which dominates the magnetic response at low temperatures and shows an interesting temperature dependent scaling behaviour when plotted as M vs B/T which we believe is related to the organo-metallic matrix that the particles are trapped within. We propose that the enhanced blocking temperature of particles synthesised using halocarbon solvents can be attributed to inter-particle dipolar interactions and nanoparticle-matrix exchange interactions.

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“…These materials have unique physical properties in spin-based electronics such as size and shape effects [9]. Studies have shown that, depending on the concentration of transition metals, DMSs can be ferromagnetic, superparamagnetic, or a spin-glass state [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Diluted magnetic semiconductor: structure, size and shape, and magnetic properties

Arucu¹

2017

Turk J Phys

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Abstract:In dilute magnetic metallic alloys, spin exchange interactions among transition metal ions at the ZnO structure cause changes in the magnetic properties of the nanocrystals depending on size and shape. The effect of size and shape on the structural and magnetic properties of semiconductors, using atomistic spin calculations, is the main topic of this study. When the size of the system decreases to a few nanometers, stability is not observed as a result of the large size. We theoretically examine the magnetic properties of CoZnO materials according to size and shape effects using the Monte Carlo method and the Heisenberg Hamiltonian VAMPIRE software package. We observe that size and shape control the magnetic disorder and temperature-dependent magnetization in Co-doped ZnO materials.

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Memory in nanomagnetic systems: Superparamagnetism versus spin-glass behavior

Cited by 124 publications

References 36 publications

Magnetic properties, exchange bias, and memory effects in core-shell superparamagnetic nanoparticles of La0.67Sr0.33MnO3

Magnetic properties, exchange bias, and memory effects in core-shell superparamagnetic nanoparticles of La0.67Sr0.33MnO3

Controlling nickel nanoparticle size in an organic/metal–organic matrix through the use of different solvents

Diluted magnetic semiconductor: structure, size and shape, and magnetic properties

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