[en] A zero-resistance state has been observed, far below the ferromagnetic Curie temperature and after cycling in a magnetic field, in a bulk sample of HoMo₆S₈ composed of a few single crystals. This new superconducting state is attributed to the percolation of superconducting ''walls''

[en] Large-volume single crystals of the superconducting phase HoMo₆S₈ have been obtained. A new method for their preparation is presented. The results obtained and the technological conditions are discussed with a view to their application for otbaining other single crystals of rare earth-molybdenum chalcogenides

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[en] We discuss some peculiarities of the conduction electron motion in the vicinity of domain walls which lead to an anisotropy of the magnetoresistance. We also discuss the case of single crystals of ErRh₄B₄ and HoMo₆S₈ where magnetoresistance with the same qualitative features has been observed

[en] The variety of morphology, chemical composition and density of holmium polysulfide crystals grown from the flux in different as well as in the same experiments is observed. It was found that the crystals of different habits have the monoclinic structure, P2₁/m, a=10.95, b=11.45, c=10.97A, β=91.3^o, as already known, and identical composition HoS_1.837. All the crystals are twinned by the plane (101-bar ). It is shown that the diversity of crystal compositions and density values are due to the constitution of the flux in a crystal and displacement of a crystal in the growth zone. The formation of non-equilibrium growth forms is discussed

[en] We report measurements of the temperature dependence of the ac and dc susceptibility of single-crystal HoMo₆S₈ oriented both parallel and perpendicular to the magnetic axis in static magnetic fields varying from 0.005 to 100 Oe. We find T/sub c/1 approx. =1.70 K and T/sub c/2 approx. =0.65 K with significant supercooling in low fields at T/sub c/1 and very long time effects associated with cooling through T/sub c/2 but not on warming. We find a significant difference between the ac and dc susceptibility changes at both transitions. The lower critical field H/sub c/1 is determined to be approx.20 Oe

[en] Crystal structures of two polysulfide phases, HoS_1.885(5) (1) and HoS_1.863(8) (2), were determined by the method of X-ray diffraction analysis, stoichiometric composition being ascertained. Unit cell parameters for crystal 1 are as follows: a = 3.820(1), c = 7.840(3) A, sp.gr. P4/nmm, Z = 2; for crystal 2 they are equal to: a = 10.961(2), b = 11.465(2), c 10.984(2)A, β = 91.27(3) deg, sp.gr. P2₁/m, Z = 24. It was ascertained that coordination number of holmium in both compounds equals 9. The Ho-S distances vary within 2.717-3.067 A irrespective of anion type, i.e. S^2- or (S₂)^2_. Structures of both compounds are referred to PbFCl structural type

[en] A number of salient experimental results obtained by small angle neutron scattering with the ternary compound HoMo₆S₈ are presented. At low temperature, this material is superconducting and shows a tendency towards ferromagnetic order. The results presented are compared with several current theories which purport to describe the microscopic nature of the ''coexistence'' of ferromagnetism and superconductivity

[en] The first neutron diffraction results obtained on single crystals of HoMo₆S₈ are reported. At temperatures below Tsub(m) = 0.65 K, HoMo₆S₈ develops a magnetic ordering of long period; the magnetic moments, aligned along the [111] direction, are perpendicular to the modulation wave vector k = [k, - k,0] (rhombohedral cell). This modulated phase can be quenched at T = 0.1 K (k = 0.008). However, by slow cooling, the modulated phase transforms into a ferromagnetic ordering with microdomains of size 1000 A to 1500 A

[en] It is shown at the example of HoMo₆S₈ that surface superconductivity in ferromagnetic materials is possible due to domain branching in the surface vicinity. The given effect explains experimental data on the presence of superconductivity in ferromagnetic normal phase of recurrent superconductors