Microscopic study of the magnetic coupling in a nanocrystalline soft magnet

Abstract

The magnetic behaviour of nanosize ferromagnetic bcc granules embedded in an amorphous tissue (i.e., partially crystallized Fe 80 Zr 7 B 12 Cu amorphous alloy) was studied by 57 Fe Mössbauer spectroscopy. The results are compared with the bulk counterparts: bcc-Fe and amorphous Fe 2 B 0.625 Zr 0.375. Size dependent enhancement of the Curie point of the nanosize amorphous phase was not observed. At temperatures well above the Curie point of the amorphous phase superparamagnetic relaxation of the bcc crystallites is observed opening new possibilities to study the anisotropy energy of nanosize ferromagnetic grains.

Enhancement of the magnetic refrigerant capacity in partially amorphous Fe70Zr30 powders obtained by mechanical alloying

“…In order to reduce the number of free parameters, the HF values of a-Fe phase was fixed using the average results of fitting at room temperature, 32.3 T (lower than that of pure Fe due to presence of Zr atoms), and a linear decrease of 0.5 T as temperature increases from 300 to 400 K, following Ref. [21,22]. Fig.…”

Mossbauer-Spectroscopy Characterization of Nanostructured Magnetic Materials

“…Mössbauer spectroscopy has been shown to be a powerful tool for magnetic and structural characterization of nanostructured magnetic alloys based on iron AKSENOVA, CHUEV [4][5][6][7][8][9][10][11][12][13]. The materials consist of nanoparticles in the form of α -Fe crystal grains embedded in an amorphous matrix.…”

“…1), a phenomenon observed in half of studies dealing with nanostructured magnetic alloys [4][5][6][7][8][9][10][11][12][13] or with other superparamagnetic-particle systems [17][18][19][20][21][22][23]. A qualitative explanation free from a continuous H hf distribution was first proposed within the GTLR model [24,25].…”

“…For a nanoscale particle, KV/k B is of order 100 K, so that all the states with arbitrary orientations of the magnetic moment relative to the axis of anisotropy are populated even at room temperature. Modern technology enables one to produce such particles [4][5][6][7][8][9][10][11][12][13].…”

Magnetic properties of nanocrystalline thin films of Fe-rich alloys

“…Ill particular, materials possessing high magnetic saturation induction, high magnetic permeability and low losses at elevated temperatures are in great demmld [2]. These re(luirements are satisfied by ternary alloys Fe-Si-B with a small addition of Nb and Cu or Fc-Zr-B alloys [3,4]. Ill particular, the soft magnetic properties with a high saturation magnetization have been found in Fe-Zr-Nb-B alloys with Zr+Nb amount of 6 at % [5].…”