Effects of Spin Fluctuations on the Magnetism of (Fe_1−xCo_x)Si

Abstract

Curie temperature and temperature dependence of the spin susceptibility for ( Fe1-,Co,)Si are calculated by taking into account the effect of spin fluctuations in the Gaussian approximation. Saturation magnetization and the low-temperature specific heat coefficients are calculated making use of the rigid band approximation. Qualitative agreement between the theoretical and experimental results is obtained.Die Curietemperatur, und die Temperaturabhangigkeit der Spinsuszeptibilitat werden fur (B'e,-,Co,)Si unter EinschluB der Spinfluktuationen in Gausscher Naherung berechnet. Die Sattigungsmagnetisierung und die Temperaturkoeffizienten der spezifischen Warme fur niedrige Temperaturen werden mittels der ,,rigid band"-Naherung berechnet. Es wird qualitative ffbereinstimmung zwischen den theoretischen und experimentellen Ergebnissen erhalten.

History dependence of the magnetic properties of single-crystalFe1−xCoxSi

“…[34][35][36][37] Due to the comparably high absolute value of the electrical resistivity and an upturn at low temperatures, 27,29,38,39 helimagnetic Fe 1−x Co x Si is often referred to as a strongly doped semiconductor. This behavior contrasts studies of both the magnetic properties [40][41][42][43][44][45][46][47] and the band structure 33,35,37,48 of Fe 1−x Co x Si consistently suggesting itinerant magnetism.…”

Effects of inhomogeneity on the magnetism of Fe1 xCoxSi

“…However, Fe 1−x Co x Si (0.1 x 0.7) compounds are magnetically ordered. By using the spin fluctuation theory [6], this interesting magnetism of Fe 1−x Co x Si was studied in [7]. In that study, the authors calculated the temperature dependence of the spin susceptibility and obtained the Curie temperature.…”

“…The above form of the non-interacting DOS comes from the DOS with the hybridization gap in the periodic Anderson model which has the hybridization V between conduction electrons and f electrons with the energy level ε f . Note that we introduce the above artificial form (7) in order to realize the structure which has a gap and a sharp peak near the gap, and also note that the values V and ε f themselves have no physical meaning in the present model. We use the Gaussian form (8) in the non-interacting DOS (7) for convenience as regards the numerical integral.…”

“…Note that we introduce the above artificial form (7) in order to realize the structure which has a gap and a sharp peak near the gap, and also note that the values V and ε f themselves have no physical meaning in the present model. We use the Gaussian form (8) in the non-interacting DOS (7) for convenience as regards the numerical integral. In the practical calculation, we take the width of the Gaussian as the energy unit (W = 1), and set V = 0.8 and ε f = 1.…”

Competing localization and quantum interference effects in Fe0.9Co0.1Si

“…Obviously, electron doping to an insulator increases the number of mobile electrons and leads to the finite number of density of states at the Fermi level and hence drives the metallic nature. Aptness of thin films of Co‐doped FeSi for spintronic device applications 8, 9, their magnetic properties and the effect of spin fluctuations 10 are reported. A survey reveals that FeSi is a nonmagnetic narrow‐gap semiconductor with a gap of ∼50 meV 11, CoSi is a diamagnetic metal 12 and MnSi is an itinerant ferromagnetic metal 13.…”