Mössbauer effect studies of Fe_100−xGa_xfilms prepared by combinatorial methods

Abstract

Magnetostrictive Fe 100−x Ga x alloys over the composition range 0 < x < 36 have been prepared by combinatorial sputtering methods. These films were investigated by x-ray diffraction and 57 Fe Mössbauer effect spectroscopy techniques that have been adapted for the efficient study of combinatorial samples. X-ray diffraction measurements show the presence of a disordered bcc phase with a lattice parameter that increases with increasing Ga content. Mössbauer effect measurements show that even for low Ga content the disordered alloys are not truly random but show some degree of short range Ga clustering. For x > 20, the Mössbauer effect results suggest the presence of short range D0 3 type order. This persists up to the maximum Ga content studied here (x = 36), although there is no evidence to support the formation of long range D0 3 structural order in any of the films prepared in this study.

Influence of the sputtering flow regime on the structural properties and magnetic behavior of Fe-Ga thin films (Ga ∼ 30 at.%)

“…The higher Ga content observed in the diffusive sample can be explained by the lower surface energy of Ga (2.78 eV) compared with Fe (4.29 eV) [28]. If we compare the lattice parameter of our samples with reported values for sputtered layers with an equivalent Ga content [11], we find reasonable values considering the rather wide range of reported parameters. We calculated the ratio between the intensity of the Fe(110) and Mo(110) diffraction peaks (I Fe(110) /I Mo(110) ).…”

“…1 we compare the XRD patterns of layers deposited with the same growth power in the ballistic and in the diffusive flow. In both cases, the main diffraction peak is related to the (110) reflection of the α-Fe structure as generally observed in Fe-Ga thin films [11,15]. The two samples also show a rather small diffraction peak corresponding to Fe(211).…”

“…The second high magnetostrictive state of the alloy is more complex. The D0 3 order appears beyond 19 at.% Ga [8], and, eventually, some papers point to the formation of Ga aggregates above 28 at.% Ga [11]. Thus, obtaining this second metastable state * Corresponding author: rociran@ucm.es seems more difficult to achieve, and identification of the nature of Ga aggregates remains to be investigated.…”

“…Although several papers deal with the growth of Fe-Ga thin films by sputtering [11][12][13][14][15][16][17], the impact of different phenomena occurring during sputtering deposition has not been completely clarified or quantified. For example, neutrals (atoms ejected from the target upon the impact of energetic particles) suffer collisions during their movement from target to substrate [18][19][20].…”

Investigation on the structural and magnetic properties of sputtered TbFe2/Fe3Ga heterostructures

“…Moreover, few works have been devoted to the investigation of Fe 1Àx Ga x thin films. [12][13][14][15][16] In a previous work, we studied the characteristics of Tb x Fe 1Àx thin films. 17 In this work, we analyze and correlate the structural and magnetic properties of as-grown and annealed [TbFe 2 /Fe 3 Ga] n heterostructures.…”