Električni transport u staklastim Zr-3d slitinama

Superconducting transition temperature, magnetic susceptibility and electrical resistivity of Zr-3d glassy alloy systems has been measured. The above properties are closely connected with the electronic structure of these alloys. Almost linear decrease of the magnetic susceptibility, temperature of the superconducting transition and the constant of the electron-photon interaction l with the concentration of 3d element show that the electronic density of states at the Fermi level is dominated with Zr d-states.These results are simply explained with the dilution effect due to increase of the concentration of 3d element. This claim has been verified with the results of the UPS experiments performed on Zr-3d alloys, and is also supported with the analysis of temperature dependence of the electrical conductivity. The calculation has shown that the electrical resistivity of glassy Zr-3d alloys can not be explained within the framework of the classical extended Ziman theory only.Mjerene su temperature supravodljivog prijelaza, magnetska susceptibilnost kao i električni otpor za niz Zr-3d slitina. Navedena mjerenja su usko povezana s elektronskom strukturom danih slitina. Gotovo linearno smanjenje magnetske susceptibilnosti, temperature supravodljivog prijelaza i konstante λ elektron-fonon interakcije s koncentracijom 3d elementa pokazuju da je gustoća elektronskih stanja na Fermijevom nivou u tim slitinama dominirana Zr d-stanjima. Rezultati se jednostavno mogu objasniti efektom razređenja s povećanjem koncentracije 3d elementa. Tvrdnju potvrđuje i analiza temperaturne ovisnosti električne vodljivosti kao i rezultati dobiveni eksperimentima UPS fotoemisije na danim slitinama. Proračuni pokazuju da električni otpor staklastih Zr-3d slitina nije moguće objasniti u okviru klasične proširene Zimanove teorije

Supravodljivost i temperaturni koeficijent električnog otpora na sobnoj temperaturi u Zr-3d staklastim slitinama

The measurements of the superconducting transition temperatures Tc and the resistivity variation, Including the room temperature coefficient of resistivity α = (d ln ρ/dT)273, have been made for three binary Zr-3d (3d=Co, Ni or Cu) amorphous alloy systems and a number of ternary Zr2(Ni100−xMx)1 amorphous alloys (M=Ti, V, Cr, Mn, Fe, Co or Cu). In binary alloys, Tc decreases with decreasing Zr-content in agreement with the results of the photoemission studies and heat capacity measurements. However, the proportionality between the electron-phonon coupling constant λ (deduced from Tc) and dρ/dT predicted by the Ziman model is not generally valid. The variation of Tc and α in ternary alloys are strongly affected by the magnetic correlations for M = Cr and Mn. The observed α < 0 for all alloys can be qualitatively explained in terms of incipient electron localization.Mjereni su temperatura supravodljivog prijelaza Tc i promjena električnog otpora s temperaturom kao i temperaturni koeficijent električnog otpora na sobnoj temperaturi α = (d ln ρ/dT)273 za tri binarna Zr-3d (3d = Co, Ni ili Cu) staklasta sistema i za niz Zr2(Ni100−xMx)1 staklastih slitina (M = Ti, V, Cr, Mn, Fe, Co ili Cu). U binarnim se slitinama Tc smanjuje sa smanjenjem Zr i to je potpuno u skladu s rezultatima eksperimenata fotoemisije i mjerenja toplinskog kapaciteta dobivenim na sličnim slitinama, koji pokazuju da se elektronska gustoća stanja na Fermijevoj razini smanjuje sa smanjenjem količine Zr. Proporcionalnost između konstante elektron–fonon interakcije λ (izračunate iz Tc) i dρ/dT, kako to predviđa Zimanov model, općenito ne vrijedi. Promjene Tc i α u ternarnim slitinama za slitine s M = Cr i Mn pod jakim su utjecajem magnetskih efekata. Uočene α < 0 za sve slitine mogu se kvalitativno objasniti efektom početne lokalizacije elektrona

Properties and atomic structure of amorphous zirconium

Wide glass-forming range in Zr-M alloys (M = late transition metal) combined with a simple, often linear, variation of their physical properties with composition makes it possible to deduce physical properties of pure amorphous zirconium. We explore this possibility by using our experimental results for the magnetic susceptibility and superconducting transition temperature of paramagnetic amorphous Zr – (Co,Ni,Cu) alloys extending over a wide composition range. By combining these results with the literature results for the low temperature specific heat of the same alloy systems, we obtained a set of parameters associated with the electronic structure of the amorphous Zr. The comparison of these parameters with the results of the electronic structure calculations for different crystalline phases of Zr and with the results of the atomic structure and initial crystallisation studies of the same alloy systems indicate a fcc-like local atomic structure for amorphous Zr

Magnetootpor u ternarnim staklastim slitinama Zr2(Ni1-xMx)1

We have measured magnetoresistivity of some ternary glassy Zr2(Ni1-xMx)1 alloys, M = Ti,V,Co and Cu, in magnetic fields up to 1.2 T at temperatures 4.2 K, 5 K, 6 K and 7 K. The magnetoresistivity of these alloys can be explained by adding contribution of the superconducting fluctuations to the contributions due to quantum coherence effects. The estimated values for inelastic relaxation times ti are very reasonable.Mjeren je magnetootpor nekih ternarnih staklastih slitina Zr2(Ni1-xMx)1, gdje je M = Ti, V, Co ili Cu, u magnetskom polju koje se mijenjalo od 0 T do 1.2 T, na temperaturama 4.2 K, 5 K, 6 K i 7 K. Pokazali smo da se magnetootpor tih slitina može objasniti dodavanjem doprinosa supravodljivih fluktuacija doprinosima koji nastaju uslijed kvantnih koherentnih efekata. Dobivene vrijednosti neelastičnih vremena raspršenja vrlo su prihvatljive

Electronic and magnetic properties of ternary Zr2(Ni1-xMx)1 glassy alloys

The electric resistivities (in the temperature range from 8 K to 300 K), the room temperature magnetic susceptibility and the superconducting transition temperature of the amorphous Zr_2(Ni_1-xMx)_1 alloys (M=Ti, V, Cr, Mn, Fe, Co, Ni and Cu) have been investigated. The temperature dependence of the electrical resistivity can be described in terms of the incipient electron localisation effects inherent to the high resistivity alloys, same as of the other Zr-3d glassy alloys (3d=Fe, Co, Cu or Ni). The new features introduced with M are the pronounced nonmonotonic variations of the magnetic and electron-transport properties with M. The origin of these variations are the systematic changes in the electronic band structure of the alloys on going from M=Cu towards M=Ti (as confirmed by the photoemission experiments on similar (Zr_67Ni_33)_85M_15 amorphous alloys) and the tendency to the formation of localized magnetic moments for M around the middle of 3d-series (M=V, Cr, Mn and Fe). A novel feature is a rather strong suppression of the effects of the incipient localization in the resistivity by the magnetic interactions

Comment on: High Mixing Entropy Enhanced Energy States in Metallic Glasses

A recent paper by Juntao Huo et al [Chin. Phys. Lett. 39 (2022) 0464011] reported a correlation between the entropy of mixing (and the corresponding energy state) and the thermal stability and mechanical parameters, for three Zr-Ti-Cu-Ni-Be metallic glasses (MG) including a high-entropy one (HEMG). The authors dismissed a possible compositional contribution to the variations of the thermal stability and mechanical parameters studied.Comment: 2 pages, 1 figur