ESR of ultrafine magnetic particles

Nagata, Kazukiyo; Ishihara, Akihiro

doi:10.1016/0304-8853(92)91459-7

Cited by 89 publications

(59 citation statements)

References 4 publications

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“…A cubic dependence is observed for the S-G samples whereas a quadratic or cubic one is suitable for the PR compounds. The dependence observed for both samples is typical of superparamagnetic systems, as empirically studied for ultrafine magnetic particles [28]. Moreover, some suggestions about the particles orientation can be obtained from these curves, even if inter-grain magnetic interactions should be also considered in our samples.…”

Section: Simple Langevin Function Does Not Allow a Satisfactory Repromentioning

confidence: 74%

Nanosized Sodium-Doped Lanthanum Manganites: Role of the Synthetic Route on Their Physical Properties

et al. 2003

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In this paper we present the results of the synthesis and characterisation of nanocrystalline La 1-x Na x MnO 3+δ samples. Two synthetic routes were employed: polyacrylamide-based sol-gel and propellant synthesis. Pure, single phase materials were obtained with grain size around 35 nm for the sol-gel samples and around 55 nm for the propellant ones, which moreover present a more broaden grain size distribution. For both series a superparamagnetic behaviour was evidenced by means of magnetisation and EPR measurements with peculiar features ascribable to the different grain sizes and morphology. Preliminary magnetoresistivity measurements show enhanced lowfield (< 1 T) magnetoresistance values which suggest an interesting applicative use of these manganites.

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Section: Simple Langevin Function Does Not Allow a Satisfactory Repromentioning

confidence: 74%

Nanosized Sodium-Doped Lanthanum Manganites: Role of the Synthetic Route on Their Physical Properties

et al. 2003

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“…According to the model of Nagata and Ishihara, [32] the shift of the resonance field, dH res (relative to a high-temperature value), and the line width, DH pp , are related by the simple ratio dH res~( DH pp ) n , in which n = 2 for partially oriented and n = 3 for randomly oriented NPs. Nagata and Ishihara assumed that the particle shape was an ellipsoid and H res was governed by the demagnetizing fields and not by the anisotropy fields.…”

Section: Resultsmentioning

confidence: 99%

“…Such behavior is found in various magnetic NP systems. [32][33][34][35][36][37] To trace the influence of the liquid-crystalline properties on NP behavior, we studied the temperature dependence of H res and DH pp at high temperatures (300-400 K) also. Temperature variations of H res and DH pp over the whole temperature range examined from 380 to 4.2 K are presented in Figure 3 a and b, respectively, for dendrimeric g-Fe 2 O 3 NPs.…”

Section: Parameters Used For the Characterization Of Emr Signalsmentioning

confidence: 99%

Magnetic Resonance and Mössbauer Studies of Superparamagnetic γ‐Fe₂O₃ Nanoparticles Encapsulated into Liquid‐Crystalline Poly(propylene imine) Dendrimers

et al. 2011

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We present the first results of electron magnetic resonance (EMR) and Mössbauer spectroscopy studies of γ-Fe(2)O(3) nanoparticles (NPs) incorporated into liquid-crystalline, second-generation dendrimers. The mean size of NPs formed in the dendrimers was around 2.5 nm. A temperature-driven transition from superparamagnetic to ferrimagnetic resonance was observed for the sample. Low-temperature blocking of the NP magnetic moments has been clearly evidenced in the integrated EMR line intensity and the blocking temperature was about 60 K. The physical parameters of magnetic NPs (magnetic moment, effective magnetic anisotropy) have been determined from analyses of the EMR data. The effective magnetic anisotropy constant is enhanced relative to bulk γ-Fe(2)O(3) and this enhanced value is associated with the influence of the surface and shape effects. The angular dependence of the EMR signal position for the field-freezing sample from liquid-crystalline phase showed that NPs possessed uniaxial anisotropy, in contrast to bulk γ-Fe(2)O(3). Mössbauer spectroscopy determined that fabricated NPs consisted of an α-Fe core and a γ-Fe(2)O(3) shell.

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“…They interpreted the cause of this as an effective anisotropy field arising due to local demagnetization fields of the inhomogeneous magnetic systems. Nagata and Ishihara 35 have performed electron spin resonance studies on MnZn ferrite particles dispersed in solid kerosene and they also observed that the resonance field moves to lower field as the temperature is decreased. This shows that the anomalous temperature dependence of low field mode could be related to presence of some small-crystallized regions with complicated magnetic order.…”

Section: E Temperature Dependence Of Fmrmentioning

confidence: 99%

Study of magnetization and crystallization in sputter deposited LiZn ferrite thin films

Dash

Prasad

Venkataramani

et al. 1999

Journal of Applied Physics

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Direct detection of magnon spin transport by the inverse spin Hall effect Appl. Phys. Lett. 100, 082405 (2012) Ferromagnetic resonance of micro-and nano-sized hexagonal ferrite powders at millimeter waves J. Appl. Phys. 111, 07E113 (2012) Tuning the cation distribution and magnetic properties of single phase nanocrystalline Dy3Fe5O12 garnet J. Appl. Phys. 111, 07A517 (2012) Evolution of crystallographic texture and magnetic properties of polycrystalline barium ferrite thick films with Bi2O3 additive J. Appl. Phys. 111, 07A511 (2012) Field-induced magnetic transition in cobalt-ferrite J. Appl. Phys. 111, 07E308 (2012) Additional information on J. Appl. Phys. with xϭ0.32 were rf sputter deposited on fused quartz substrates at ambient temperature. The as-deposited films were found by x-ray diffraction to be amorphous but magnetic, and showed large high field susceptibility. The films were studied after they were annealed at various temperatures up to 850°C. It was observed that the films crystallize upon annealing and the value of the saturation magnetization increases with annealing temperature. The high field susceptibility, on the other hand, decreases with increasing anneal temperature. The measured ferromagnetic resonance spectra of these films indicated that the films consist of at least two different magnetic materials. A significant portion in the film crystallizes and the value of saturation magnetization of this portion tends to the bulk value as annealing temperature is increased. However, a small portion of the film remains in a highly defective state all through, even up to annealing temperatures of 850°C. The high field susceptibility data indicates that point defects could play an important role in determining the magnetic properties of these films.

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ESR of ultrafine magnetic particles

Cited by 89 publications

References 4 publications

Nanosized Sodium-Doped Lanthanum Manganites: Role of the Synthetic Route on Their Physical Properties

Nanosized Sodium-Doped Lanthanum Manganites: Role of the Synthetic Route on Their Physical Properties

Magnetic Resonance and Mössbauer Studies of Superparamagnetic γ‐Fe₂O₃ Nanoparticles Encapsulated into Liquid‐Crystalline Poly(propylene imine) Dendrimers

Study of magnetization and crystallization in sputter deposited LiZn ferrite thin films

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ESR of ultrafine magnetic particles

Cited by 89 publications

References 4 publications

Nanosized Sodium-Doped Lanthanum Manganites: Role of the Synthetic Route on Their Physical Properties

Nanosized Sodium-Doped Lanthanum Manganites: Role of the Synthetic Route on Their Physical Properties

Magnetic Resonance and Mössbauer Studies of Superparamagnetic γ‐Fe2O3 Nanoparticles Encapsulated into Liquid‐Crystalline Poly(propylene imine) Dendrimers

Study of magnetization and crystallization in sputter deposited LiZn ferrite thin films

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Magnetic Resonance and Mössbauer Studies of Superparamagnetic γ‐Fe₂O₃ Nanoparticles Encapsulated into Liquid‐Crystalline Poly(propylene imine) Dendrimers