The formation of orbital moments on iron impurities in Ag _{1 − x} Au _x alloys

Abstract

Using the high specificity and sensitivity of the in-beam perturbed γ-ray angular distribution method, we have investigated the magnetic behavior of very dilute 54 Fe probes in Ag1−xAux alloys. The nuclear damping time and local susceptibility of Fe are found to depend strongly on its local environment, showing inhomogeneous line broadening as well as discrete magnetic responses due to the different configurations of Ag/Au nearest neighbors. The results can be understood with the aid of ab initio calculations of electronic structure, magnetic moments and hyperfine fields. They underline the central importance of orbital magnetism for understanding the experimental results.

Kondo Decoherence: Finding the Right Spin Model for Iron Impurities in Gold and Silver

“…As the calculated defect formation energy of an Fe interstitial was found to be about 2 eV higher than the energy of a substitutional defect, we discuss the latter case in the following. This is in line with experiments on Fe-implantation in AgAu alloys, where only substitutional Fe-atoms are found [16]. Fig.…”

“…The spin and orbital moments are given in the legends of Fig. 1 (spin-polarized Korringa-Kohn-Rostoker calculations yielded similar values [16]): Within spin-polarized LDA a large spin moment µ S of approximately 3-3.1 µ B forms spontaneously, consistent with Mösbauer measurements that give 3.1-3.2 µ B for the spin moment for Fe in Ag [6]. In contrast, there is no tendency for a sizable orbital moment (or a Jahn-Teller distortion).…”

Highly unquenched orbital moment in textured Fe-phthalocyanine thin films

“…8 In the limit of atomic size, that is, as atomic impurities in solids, the orbital moment may be only partially quenched, with values approaching the free atom ones. 9,10 In this paper, in drastic contrast to all above cases, we present a direct proof of the presence of a very large, highly unquenched orbital moment m L = 0.53Ϯ 0.04 B in a lowsymmetry, planar Fe͑II͒-Phthalocyanine ͑FePc͒ molecule.…”

Validity of bond-length and Mössbauer parameters to assign oxidation states in multicomponent oxides: Case study ofSr4Fe4O11

“…In some cases B orb is positive and comparable to B FC , and hence, the resulting HF is smaller than that originating from the FC term alone. 50 In some cases, B orb is much larger than B FC and the net HF will then be decided by the orbital moment. 51 The B orb can be obtained by including spin-orbit coupling into the calculation in addition to the spin polarization.…”