Mössbauer study of very dilute Pd(Fe) alloys at very low temperatures

Spin fluctuations of isolated Fe impurities in Pd-based dilute alloys: effect of ferromagnetic host spin polarization

“…The results derived for different solutes are summarized in table 1. The μ T and S h values, estimated using B(0) values taken from [22][23][24] and S imp ∼ 1.75 corresponding to Fe magnetic moment μ Fe ∼ 3.5 μ B [11], are also shown in table 1. For Fe in pure Pd metal, the observed total moment μ T ∼ 11.5 μ B reflects the existence of a giant moment with a large ferromagnetic spin polarization S host = 3.95 of Pd 4dband electrons, consistent with the results reported earlier [10][11][12].…”

Determination of the 57Co hyperfine field in Pd(57Co) from Mössbauer emission spectra in the regime of fast relaxation

“…The constants a~, a2 and a3 are determined by the population in the 5'Co levels and the transition probabilities to the different ~Fe(7 = 5/2) levels. Inserting (9) in (3) and 3in (2) we finally find that in the presence of relaxation the average density matrix of the 7 = 3/2 ) state is : " Using eqs. (7), (8), (10) we now can derive the analytical form of the resonance spectrum (Eq.1) which is no more than a sum of broadened Lorentzian lines in the positions rom el m g of the nuclear transitions (I 7 = 3/2, IZ = ~ ) ~ !…”

“…Mossbauer spectroscopy on dilute alloys which stay paramagnetic down to lowest temperatures is essentially stimulated by questions concerning the formation of giant moments and the compensation of local moments. In some favourable examples, like Pt(Fe) or Pd(Fe) it is even possible to observe the slowing down of the impurity spin-conducting electron relaxation using Mossbauer emission spectroscopy on pt(57CO) and Pd(57Co) [1,2]. From these experiments the 57 Fe hyperfine magnetic field jSã s a function of applied external magnetic field B and temperature T is determined.…”

“…by yl. We stress that the approximation involved is Yjj, y~ ~ A 1 ~ In (10) and (11) we keep all terms in the expansion with ~w~ /kB T, whereas we neglect terms higher than first order in ~S~a ~ sincẽ F ~ ~ ~2.~/~ -2.4 x 10s s -1 [2],…”