We have reported the discovery of a superconducting HEA Ta-Nb-Hf-Zr-Ti, which shows a high superconducting transition temperature (for a metallic system) of 7.3 K and a large upper critical field of 8.2 T. We have studied the superconducting transition in samples of different chemical composition subjected to different thermal annealing procedures and showed that the superconductivity is a robust phenomenon.
COBISS.SI-ID: 30087463
By performing measurements of the magnetic properties, the specific heat and the electrical resistivity in a magnetic field, we have determined the magnetic state of the Ce-Gd-Tb-Dy-Ho HEA. Long-range-ordered periodic magnetic structures do not form, but the magnetic structure breaks up into ferromagnetically (FM) polarized spin domains distributed in size that orient randomly in zero field. The magnetically ordered state of the Ce-Gd-Tb-Dy-Ho HEA can be described as a disordered FM state with random local anisotropies.
COBISS.SI-ID: 31198247
We have investigated the magnetism of CoCrFeNiZrx (x = 0.4 – 0.5) eutectic high-entropy alloys (HEAs) in relation to their microstructure. Two structural phases develop in the CoCrFeNiZrx HEAs, a Zr-free fcc solid solution and a Zr-containing C15 Laves-phase intermetallic compound. Two magnetic structures coexist in the CoCrFeNiZrx HEAs. The first is a disordered ferromagnetic phase that develops in the interior of large dendrites of the fcc solid solution and in some larger lamellas of this phase. The second phase is superparamagnetic-like and originates from the remaining spins of the fcc solid solution fraction and from all spins of the C15 Laves-phase fraction. The magnetism of multi-phase HEAs containing magnetic elements cannot be described as a compositional average of magnetic properties of the constituent phases.
COBISS.SI-ID: 30976039
We have investigated the magnetic phase diagram and the magnetoresistance of a Gd-Tb-Dy-Ho-Lu "ideal" hexagonal high-entropy alloy (HEA), composed of the elements from the heavy half of the rare earth series only. The phase diagram is very rich, containing an antiferromagnetic (AFM) state, a field-induced ferromagnetic (FM) state above the AFM-to-FM spin-flop transition and a low-temperature spin-glass state. The magnetoresistance reflects complexity of the (H,T) phase diagram, changing from an AFM to a FM type with an increasing magnetic field.
COBISS.SI-ID: 31948327
We reported on the discovery of a magnetically soft high-entropy alloy of composition FeCoNiPdCu, which performs comparably to the best commercial soft magnets for static and low-frequency applications. Properly heat-treated FeCoNiPdCu develops nanostructure that can be viewed as a two-phase bulk nanocomposite of randomly intermixed FeCoNi magnetic domains and PdCu nonmagnetic "spacers". Due to the nanometric size, the FeCoNi domains are magnetically single-domain particles, and since the particles are exchange-coupled across the boundaries, exchange averaging of magnetic anisotropy takes place, resulting in an almost vanishing coercive field and excellent magnetic softness.
COBISS.SI-ID: 32146727