Magnetization and magnetoresistance study of amorphous FexPd82−xSi18

Abstract

We find that amorphous FexPd82−xSi18 undergoes a transition from spin glass (x≲5) to ferromagnetic (x?25) through an intermediate state (x?10 –20). In Fe25Pd57Si18, magnetic order persists at room temperature. The importance of spin fluctuations in the spin glass, intermediate and ferromagnetic regimes is indicated by the negative magnetoresistance at 4.2 K which does not saturate up to ∼230 kOe.

Magnetic transitions in FexPd82−xSi18 metallic glasses

“…A further increase of x above = 15 at:/, Fe improves the coupling between clusters thereby reducing again large scale inter-cluster fluctuations. This tentative account is consistent with the observed coercivity maximum a t = 10 atyo Fe, the composition dependence of the dc low field magnetization maxima, the low field Arrott "tails", and the high field magnetoresistance [15]. Apparently, the various transition temperatures and in particular M ( z ) and M,(x) are not as sensitive to the distribution of Fe in the amorphous matrix and increase monotonically with x. Annealing studies are required to establish the role of inhoniogeneities in the magnetic ordering of a-Fe,Pds2-,Si18.…”

Magnetic properties of metallic glasses of the type Fe80−x Pd x B20 and Fe80−x Pt x B20

“…We continue our previous studies of theses materials [1,2] which are also interesting for others and have been measured with Si instead of B in [3,4] and with low Fe concentration in [3] in which there is expected an effect of "giant magnetic moment" (like 12 μ B per Fe atom for about 0.28 at. % Fe in Pd).…”

“…The increase of this value for higher Pd concentrations is evidently due to Pd magnetic moments of 4 day shells which interact with Fe magnetic moments and enlarge average value. Hyperfine magnetic field does not reflect such Fe magnetic moments increase, so as discussed in [4] this is an effect of Pd atoms (with about 0.4 μ B per Pd atom as found in [7] for crystalline Fe-Pd system). A good illustration of this is the alloy Fe 30 Pd 50 Si 12 B 8 as seen from Table I and Figure 1 where the value of average magnetic moment per Fe atom is 3.37 μ B with H max =255 kOe only compared to Fe 80 B 20 alloy where these values take 2.01 μ B and 290 kOe, respectively.…”

“…One of the first metals obtained as a metallic glass was Pd-Si alloy because of easy creation. Both crystalline and amorphous Pd-Fe alloys (see [4] for Pd-Fe-Si system) are nonmagnetic when Pd is high, and then start to be ferromagnetic when Fe concentration is big enough. There is also a spin glass state reported for Fe x Pd 80−x Si 20 at x in the range 1<x<7 [4,5].…”

“…Both crystalline and amorphous Pd-Fe alloys (see [4] for Pd-Fe-Si system) are nonmagnetic when Pd is high, and then start to be ferromagnetic when Fe concentration is big enough. There is also a spin glass state reported for Fe x Pd 80−x Si 20 at x in the range 1<x<7 [4,5]. 57 Fe Mössbauer spectroscopy was applied already to study Fe x Pd 80−x Si 20 alloys with low Fe concentrations in [3].…”