ZIB

1

Digitale Medien

Microstructure and magnetization reversal in nanocomposite SmCo5/Sm2Co17 magnets (2002)

Yan, A. ; Bollero, A. ; Gutfleisch, O. ; [weitere]

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 91 (2002), S. 2192-2196

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7550

Quelle: AIP Digital Archive

Thema: Physik

Notizen: A comparative investigation has been made of the microstructure and magnetization reversal behavior of nanocomposite SmCo5/Sm2Co17 powders prepared by intensive milling and subsequent annealing. It was found that the saturation magnetization increases monotonically with the increase of the volume fraction of Sm2Co17 at the expense of the coercivity. However, the remanence and the energy product first increase and then decrease with further increase of the fraction of Sm2Co17. The highest remanence of 0.72 T and energy product of 78 kJ/m3 are obtained in the powders with 80% and 60% Sm2Co17, respectively. All the hysteresis loops exhibit a magnetically single-phase behavior. X-ray diffraction results reveal that the coexistence of two phases is found in the mixture of SmCo5/Sm2Co17 powders. The demagnetization processes of the SmCo5/Sm2Co17 powders are similar to those of nanocomposites consisting of hard and soft phases, in which the exchange-spring magnet behavior was observed. Positive as well as negative deviations in Wohlfarth's remanence analysis (δM-plot) have been observed, indicating complex magnetic interactions in these materials. © 2002 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.1433940

Permalink

Bibliothek	Standort	Signatur	Band/Heft/Jahr	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

2

Digitale Medien

Fast development of high coercivity in melt-spun Sm(Co,Fe,Cu,Zr)z magnets (2002)

Yan, A. ; Bollero, A. ; Müller, K. H. ; [weitere]

Woodbury, NY : American Institute of Physics (AIP)

Applied Physics Letters 80 (2002), S. 1243-1245

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1077-3118

Quelle: AIP Digital Archive

Thema: Physik

Notizen: A simple method was developed for magnetic hardening melt-spun Sm(Co,Fe,Cu,Zr)z alloys. The as-spun ribbons reached a coercivity of 2.8 T only by slow cooling from 850 to 400 °C, without the standard solid solution and isothermal aging treatments which are required for a bulk precipitation hardened 2:17 SmCo alloy. A single 1:7 phase, identical to that found in as-solubilized ribbons, was obtained in the as-spun state. At the same time, Cu and Zr are supersaturately dissolved in the 1:7 matrix by melt spinning due to its very high cooling rate. Thus, solid solution treatment can be avoided for melt-spun materials. After aging, more lamellar phase with larger width was observed by transmission electron microscope in ribbons without treatment in solution. This leads to faster development of a uniform finer cellular microstructure with a Cu-rich 1:5 cell boundary phase, which gives rise to stronger domain-wall pinning and therefore to higher coercivity. © 2002 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.1450253

Permalink

Bibliothek	Standort	Signatur	Band/Heft/Jahr	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

3

Digitale Medien

Phase separation in Nd60−xYxFe30Al10 melt-spun ribbons (2002)

Sun, Z. G. ; Löser, W. ; Eckert, J. ; [weitere]

Woodbury, NY : American Institute of Physics (AIP)

Applied Physics Letters 80 (2002), S. 772-774

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1077-3118

Quelle: AIP Digital Archive

Thema: Physik

Notizen: The structure of melt-spun Nd60−xYxFe30Al10 (x=0, 10, and 30) ribbons has been investigated by x-ray diffraction, isochronal differential scanning calorimetry (DSC), isothermal DSC, and thermomagnetic measurements. Precipitation of nanocrystalline Nd embedded in an amorphous matrix is found upon quenching. The amorphous phase further separates into Fe-rich regions and Fe-depleted regions. The growth of Nd nanocrystals upon annealing was identified by the characteristic isothermal calorimetric signal. The Fe-depleted amorphous phase crystallizes at 580 K, while the Fe-rich amorphous phase crystallizes at about 740, 779, and 750 K for x=0, 10, and 30, respectively. Phase separation in the amorphous matrix is also revealed by the thermomagnetic measurements, which show ferromagnetic transitions at about 60 and 480 K. © 2002 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.1447324

Permalink

Bibliothek	Standort	Signatur	Band/Heft/Jahr	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

4

Digitale Medien

Improved superconducting properties in nanocrystalline bulk MgB2 (2002)

Gümbel, A. ; Eckert, J. ; Fuchs, G. ; [weitere]

Woodbury, NY : American Institute of Physics (AIP)

Applied Physics Letters 80 (2002), S. 2725-2727

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1077-3118

Quelle: AIP Digital Archive

Thema: Physik

Notizen: High density nanocrystalline MgB2 bulk superconductors with distinctly improved pinning were prepared by mechanical alloying of Mg and B powders at ambient temperatures followed by hot pressing. The nanocrystalline samples reveal high jc=105 A/cm2 at 20 K and 1 T together with an irreversibility line strongly shifted towards higher fields resulting in Hirr(T)∼0.8 Hc2(T), whereas typically Hirr(T)∼0.5 Hc2(T) is observed for untextured bulk samples. These values exceed those of all other reported bulk samples and are in the range of values for thin films. The improved pinning of this material, which mainly consists of spherical grains about 40–100 nm in size, is attributed to the large number of grain boundaries in the nanocrystalline state. © 2002 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.1469654

Permalink

Bibliothek	Standort	Signatur	Band/Heft/Jahr	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext