Superconductivity and short-range order in metallic glassesFexNi1−xZr2

Abstract

In amorphous superconductors, superconducting and vortex pinning properties are strongly linked to the absence of long range order. Consequently, superconductivity and vortex phases can be studied to probe the underlying microstructure and order of the material. This is done here from resistance and local magnetization measurements in the superconducting state of FexNi1−xZr2 metallic glasses with 0 ≤ x ≤ 0.6. Firstly, we present typical superconducting properties such as the critical temperature and fields and their dependence on Fe content in these alloys. Then, the observations of peculiar clockwise hysteresis loops, wide double-step transitions and large magnetization fluctuations in glasses containing a large amount of Fe are analyzed to reveal a change in short range order with Fe content.

Superconductivity in CuAl2-type Co0.2Ni0.1Cu0.1Rh0.3Ir0.3Zr2 with a high-entropy-alloy transition metal site

“…Furthermore, as summarized in Table I, all of the TrZr 2 (Tr = Co, Ni, Rh, Ir) compounds exhibit superconductivity with T c = 5.5, 1.6, 11.3, and 7.5 K, respectively [27]. Although FeZr 2 is a superconductor, its T c is lower than 1 K [28,29]. In the case of Tr = Cu, CuZr 2 has a CuZr 2 -type (I4/mmm) structure, but partial substitution of Cu for the CuAl 2 -type compounds is possible and positively affects T c .…”

Superconductivity of high-entropy-alloy-type transition-metal zirconide (Fe,Co,Ni,Cu,Ga)Zr2

“…Figure 5 shows the temperature dependence of magnetic susceptibility measured after ZFC and FC. A large diamagnetic signals were observed below 2.9 K, which indicates the emergence of bulk superconductivity below T c = 2.9 K. Figure 6 shows the temperature dependence of electronic specific heat (C el /T), where C el was calculated by subtracting phonon contribution (βT 3 ) estimated from the low-temperature-limit formula of C = γT + βT 3 . γ is electronic-specific-heat coefficient and was estimated as 19.03(4) mJ K −2 mol.…”

“…Transition-metal zirconides (TrZr 2 ) are superconductors with a wide range of transition temprature: T c = 1.6, 5.5-6.0, 11.3, 7.5 K for Tr = Ni, Co, Rh, Ir, respectively [1]. The flexible solution at the Tr site is possible, and T c is tuned by the Tr-site solution [2][3][4]. In addition, CoZr 2 exhibits a large enhancement of T c under pressures, which suggests that the superconducting properties of TrZr 2 are sensitive to crystal-structure modification [5].…”

Ferromagnetic element microalloying and clustering effects in high B s Fe-based amorphous alloys

“…Moreover, microalloying Co and Ni will also change the inhomogeneous and the hyperfine parameters, which have been related to the changes in the short-range order [10,11]. These changes are promising for improving the Bs by increasing the magnetic interactive effect and promoting the precipitation of α-Fe(Co,Ni) clusters.…”