Comparative study of the structure and magnetic properties of Co-P and Fe-P amorphous alloys

Abstract

We present the structural parameters of a complete series of Co 1Ϫx P x (xϭ0.17Ϫ0.26) amorphous alloys as obtained by the analysis of x-ray absorption fine structure measurements. To investigate their correlation with the magnetic properties, we have performed magnetization measurements in the same set of samples, obtaining the concentration dependence of the saturation magnetization, Curie temperature, and the behavior of the low-temperature magnetization. The results for the Co-P system are then compared with the ones of amorphous Fe-P, in order to clarify whether the different structural features found can be used to explain the different behavior of the magnetic properties that these systems exhibit. The evolution of the spontaneous magnetization with the metalloid content is the same for both systems. The Curie temperature decreases appreciably in Co-P, while remaining unchanged in Fe-P. The main result of the structural analysis shows that the bonding distances between metal atoms increases in the Co-P system, whereas they do not change in Fe-P. These magnetic and structural differences are correlated in basis of simple magnetic models.

Magnetic behavior of amorphous CoP cylinder arrays

“…%, in agreement with previous results. 7,21 The decrease in moment is caused by the dilution of the cobalt ions in the films and by the reduction in Curie temperature with increasing P content. 22,23 The coercivity H C falls rapidly from ϳ300 Oe to around 10-20 Oe at 15-19 at.…”

“…The microstructure and magnetic properties of the materials depend on the composition, and can be controlled by varying the electrodeposition conditions such as the electrolyte and the current density. [7][8][9][10] Typically the materials are crystalline for low metalloid content, but become increasingly fine grained and eventually amorphous as the metalloid content increases. Simultaneously, the saturation moment decreases with increasing metalloid content.…”

“…Simultaneously, the saturation moment decreases with increasing metalloid content. 7,8,11,12 As an example, Ni 100Ϫx P x is amorphous for xϾ15 at. %, and the saturation moment decreases linearly with increasing x, reaching zero at 20 at.…”

A generalized polytetrahedral cluster approach to partial coordination numbers in binary metallic glasses

“…For instance, Hirata et al's [38] electron diffraction studies on Fe 100Àx B x metallic glasses with x ¼ 14, 17 and 20 support our statement that N cls BÀA is constant (or expected to be nearly constant) below X BA B because N exp BÀA values they listed are almost the same for all compositions. In addition to that, from the detailed structural investigations of Garcı´a-Arribas et al [42] on Co-P alloys, it can be deduced that for 17 and 18 at.% P content, N exp BÀA is almost constant, whereas after increasing the P content to 20, 22 or 24 at.% a trend of decline is observed in N exp BÀA . Although model estimations also show such a transition at that composition interval but with varying N cls BÀA 's at 17 and 18 at.% P due to significantly altered R ji data, this does not obscure the fact that observed trend in Co-P system supports the general framework behind the current model.…”

Amorphous Co-Ni-P Alloys with High Saturation Magnetization Produced by Electrodeposition

“…Among magnetic amorphous materials, Cobased alloys are important and have been produced by various techniques including rapid quenching, 18,19) physical vapor deposition, 20) chemical or electroless plating 21,22) and electrodepostion. [23][24][25][26][27][28][29] The alloys produced by electrodepostion include Co-P, Co-W and Co-Ni-P etc. It is known that these Co-based magnetic alloys have relatively low saturation magnetization values below 1.0 T. Recently, Myung et al 30) have produced Co-Ni-P crystalline alloys having high cobalt and low phosphorus contents.…”