Superconductivity and magnetism on flux-grown single crystals of NiBi3

Abstract

We present resistivity, magnetization, and specific-heat measurements on flux-grown single crystals of NiBi 3 . We find typical behavior of a type-II superconductor, with, however, a sizable magnetic signal in the superconducting phase. There is a hysteretic magnetization characteristic of a ferromagnetic compound. By following the magnetization as a function of temperature, we find a drop at temperatures corresponding to the Curie temperature of ferromagnetic amorphous Ni. Thus, we assign the magnetism in NiBi 3 crystals to amorphous Ni impurities.

Singlet superconductivity in a single-crystal NiBi3 superconductor

“…NiBi3 SCs have been studied before. While it has been found that ferromagnetism and superconductivity can coexist in NiBi3 nanostructures [17], ferromagnetism has not been found in bulk single crystals [18][19][20]. In this work, the gap value and symmetry, spin states and T dependence of the gap all demonstrate that the bulk NiBi3 sample is a singlet swave SC.…”

“…Coexistence of ferromagnetism and superconductivity has been previously observed in NiBi3 nanostructures [17]. But later experiments did not find ferromagnetism in NiBi3 single crystals [18][19][20]. It has also been shown that Bi/Ni bilayers have p-wave triplet superconductivity [42,43].…”

“…Using this technique, several SCs have been shown to have the coexistence of ferromagnetism and superconductivity including ErRh [10,11], ErNi2B2C [12], UGe2 [14], URhGe 15], NiBi3 [17]. For magnetic SCs, the triplet nature often requires further verification because these materials often contain magnetic elements where sample uniformity and purity may also cause ferromagnetism in the samples [18][19][20]. Verification of triplet SCs, especially those that can carries spin angular momentum, is essential for understanding fundamental mechanism of unconventional superconductivity as well as important applications in quantum computing [21] and spintronics [22].…”

Phase evolution in thermally annealed Ni/Bi multilayers studied by X-ray absorption spectroscopy

“…12 NiBi 3 is traditionally synthesized by heating Ni and Bi in 1 : 3 ratio at high temperature for several hours/days. Silva et al 13 have synthesized NiBi 3 crystals by heating Ni and Bi in a quartz ampule at 1100 1C for 4 h. They obtained NiBi 3 along with some Ni impurity which shows ferromagnetic behaviour. Esmeralda et al 14 have synthesized impurity Ni free NiBi 3 by heating at 1000 1C for 7 days and have found that NiBi 3 is a type II superconductor which shows ferromagnetism in superconducting phase.…”

Anisotropic superconductivity and elongated vortices with unusual bound states in quasi-one-dimensional nickel-bismuth compounds

“…Fortunately, we measure the lattice parameter of a = 8.15 Å from the real space STM image, as discussed above. Although some early studies indicated the coexistence of superconductivity and ferromagnetism in NiBi 3 [23][24][25] , the recent work reveals that it might be amorphous Ni residuals to bear the responsibility for the magnetic signal 26 . As drawn in Fig.…”