Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Magnetic properties of ultrafine nickel particles : The 5th Joint MMM−Intermag Conference (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 5903-5905 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Ultrafine nickel particles have intriguing physical and chemical properties, which are interesting both in fundamental and applied research. The size of the particle was controlled by gas pressure. X-ray diffraction studies showed that fine Ni particles have fcc crystal structure and are coated with thin Ni oxide on the surface. Electron micrographs showed a spherical particle shape, forming a long chain. Size dependence of magnetic properties were studied. The specific magnetic moment drastically decreases when reducing the diameter d of particles 〈15 nm. The coercivity Hc also approaches zero when d is about 15 nm. Therefore, we can suppose that the critical size for superparamagnetism at room temperature is about 15 nm. According to the superparamagnetic formula KV=25 kT, the value of the magnetic anisotropy constant can be determined, K = −5.8 × 105 (erg/cc). It is found to be larger than bulk Ni [K=−3.4–5.1 × 104 (erg/cc)], the same as Fe particles. The maximum of coercivity at room temperature is about 250 Oe, that is less than the theory value for the coherent rotation model, Hc = 4 K/3Ms=1600 Oe. The mechanism of reversal magnetization can be understood by the sphere chain model. The critical diameter of the single domain is about 65 nm. Curie temperature Tc obviously decreases for 9-nm average diameter particles rather than bulk. It may be in connection with the lattice contraction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350101
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Ferromagnetic resonance study on Fe-SiO2 granular films (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 6679-6682 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Ferromagnetic resonance (FMR) measurement was performed at the frequency of 9.8 GHz and at the room temperature on a series of Fe-SiO2 granular films fabricated by the Ar+-beam sputtering technique. Our results indicated that when the iron volume fraction (fv) of the films exceeds 0.28, the FMR spectra are superpositions of volume modes and surface modes. The analysis on the effective anisotropy field suggests that the intrinsic anisotropy (including the volume and interface one) becomes maximal when fv near the percolation threshold (fp). In particular, it was found for the films with fv=0.42 that the spin wave resonance modes satisfy the relation Hres∝n with a separation field of about 174 Gs between the successive modes. Our study reveals that Fe particles are coupled by a yet unknown interparticle interaction when fv is just below fp. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360489
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Microstructure and magnetic properties of rapidly quenched Sm2(Fe,Al,Zr)17C1.5 ribbons with Zr additions (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 82 (1997), S. 6351-6353 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effect of Zr additions on the microstructure and magnetic properties of melt-spun Sm2Fe(15.5−x)ZrxAl1.5C1.5 alloys has been systematically studied. The additions of Zr to Sm2(Fe,Al,Zr)17C1.5 alloys result in the precipitation of a ZrC compound within intergranular regions. It is found that the Zr addition is helpful in eliminating free iron dendrites, and effective on inhibiting grain growth during annealing. The x-ray diffraction analysis and transmission electron microscopy observation show that annealed ribbons with the Zr addition consist of a multiphase of the 2:17-type carbide, α-Fe and ZrC compound with an average grain size of about 25–35 nm. A remanence of up to 55 emu/g along with a coercivity of up to 11.6 kOe is obtained for Sm2Fe15.3Zr0.2Al1.5C1.5 ribbons annealed at 750 °C for 30 min. It is suggested that the high coercivity and remanence may be attributed to the Zr addition. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.366527
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Structural and magnetic evolution of rapidly quenched Sm–Fe–Si–C alloys (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 82 (1997), S. 5054-5056 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Sm2Fe15.5Si1.5C1.5 samples with a rhombohedral Th2Zn17-type structure have been prepared by high frequency induction melting. The crystallization, crystal structure, and magnetic properties of melt-spun and annealed ribbons have been studied by means of x-ray diffraction, scanning electron microscopy, differential thermal analysis, and magnetic measurements. The results show that the as-spun ribbons consist mainly of an amorphous phase, and that they crystallize in two steps. Upon annealing at 660 °C the ribbons form a metastable phase of the TbCu7-type and an α-Fe phase. Upon further annealing above 750 °C the metastable phase transforms to a 2:17-type phase coexisting with α-Fe. A saturation magnetization of up to 108 emu/g with a coercivity of up to 3.5 kOe is obtained in the ribbon annealed at 660 °C for 30 min. However, the reduced remanence of the ribbon σr/σs is only 0.6 and its hysteresis loop exhibits two independent magnetic components. Additionally, the grain size of the ribbons obtained by annealing at or above 660 °C for 30 min is much larger than the single domain size. Thus, it appears that there is no significant exchange coupling between the hard and soft magnetic phases of the ribbons. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.366378
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Magnetic properties of fine iron particles (1987)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 3314-3316 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Iron particles were prepared by a gas evaporation method in a nitrogen atmosphere. The particle size, shape, and magnetic properties were influenced by the nitrogen pressure. Particles prepared by this method were relatively stable in air and were not seriously oxidized. The recoilless fraction is low for the oxide layer, so that it cannot be detected at room temperature by Mössbauer spectrum. A superparamagnetic peak associated with the oxide microcrystal layer did not occur in the Mössbauer spectra due to the action of the magnetic field from the iron core and the interaction between iron particles and the low Debye temperature. From the electron micrography, the magnetic reversal process seems to be determined by a chain-of-spheres mechanism but Hc∼T curve cannot coincide with the Ms∼T curve at low temperatures. An increase of Hc may be associated with magnetic anisotropy. It is found that the magnetization versus temperature shows an anomalous increase in M(T) at higher T. We think that this means that the surface oxide layer was not magnetized to saturation even under 40 kOe at 5.5 K as the surface anisotropy is rather large.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.338893
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    A study of the magnetic properties of cobalt ferrite-coated zinc ferrite particles (1987)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 3886-3888 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Nearly spherical Zn0.2Fe2.8O4 particles coated with an epitaxial layer of CoFe2O4 ferrites of various thicknesses were studied with Mössbauer spectroscopy. Measurements reveal that the magnetic structures of these particles are different at room temperature and liquid nitrogen or liquid helium temperatures, indicating the existence of a Verwey transition, which occurs between 77 and 119 K. Coating of Co-ferrite has no sizable effect on the transition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.338598
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Effect of cobalt-ferrite epitaxial layer on the coercivity of ZnFe-ferrite particles (abstract) (1987)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 3898-3898 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Zn0.2Fe2.8O4 particles were prepared and coated with different amounts of cobalt-ferrite. The coercivity increases with increasing cobalt-ferrite coating. In the low Co-ferrite coating regime, the increase is induced by an enhanced anisotropy of the interface layer, while in the high coating regime, it is due to the Co-ferrite surface layer. The full depth of the interface layer was found to be approximately 8 A(ring), and the temperature dependence of the change in coercivity in both low and high Co-ferrite coating regimes was discussed. Mechanisms leading to a greatly increased coercivity of acicular Co-γ-Fe2O3 were also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.338602
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Monte Carlo Simulation of Configurational Anisotropy of Magnetic Cluster (2005)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 475-479 (Jan. 2005), p. 3161-3164 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In this paper, the spin configuration and the configurational anisotropy of the clusterswere studied by Monte Carlo simulations. An easy magnetization directions and a configurational anisotropy were found for the clusters using the hysteresis and spin configurations in different magnetization processes, and the simulated natural angle and energy distribution. It is considered that the configurational anisotropy is mainly attributed to the non-uniformity in spin configurations
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/09/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.475-479.3161.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Reorientation Phase and Striped Domain Patterns of Thin Films (2005)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 475-479 (Jan. 2005), p. 3165-3168 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A ferromagnetic monolayer with competing long-range dipolar interaction, short-range interaction and magnetic uniaxial anisotropy is studied using Monte Carlo simulation. Striped domain patterns are found and reveal the microstructure of the magnetization transition at the ground state via the competing between dipolar interaction and uniaxial anisotropy. We present the finite temperature phase diagram and find a temperature-induced magnetization reorientation from out-of-plane to in-plane phase. The influence of the various interactions on the structure of thestriped phase and reorientation behavior has been discussed
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/09/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.475-479.3165.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Effect of Crystal Size on the Magnetic Entropy Change in CoCr〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 121-123 (Mar. 2007), p. 889-892 
    Details
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: The size effect of magnetocaloric effect (MCE) in CoCr2O4 has been investigated bycomparing two samples with different crystal sizes. One is bulk CoCr2O4 sample (referred as A),and the other is a nanocrystalline CoCr2O4 sample (referred as B). It has been found that crystal sizedramatically affects the magnetic properties and MCE for CoCr2O4, and that the nanocrystallinematerial is more favorable for application than the bulk material. The above results are explained interms of the effect of small size and its distribution for sample B on the intrinsic magneticproperties and magnetic entropy change
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/23/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.121-123.889.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...