Magnetic field-induced superconductivity in the ferromagnetic state of HoMo6S8 (original) (raw)
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The Study of Interplay of Singlet Superconductivity and Ferromagnetism in Superconducting HoMo6Se8
SINET: Ethiopian Journal of Science
This article reports the effect of magnetic ordering and superconducting order parameter on superconducting and magnetic transition temperatures of interacting singlet superconductivity and ferromagnetism in HoMo6Se8 material. The basic superconducting parameters were calculated starting with the BCS type model Hamiltonian and using the double time temperature dependent Green function formalisms. Results showed that the superconducting critical temperature decreases with enhancement of superconducting order parameter and vice versa. This is perhaps due to the weakening of the binding energy as the temperature approaches its critical value. On the other hand, the superconducting critical temperature demonstrates attenuation with increasing magnetic order parameters . It was also observed that the enhancement of magnetic transition temperature with the increase of the magnetic order parameter demonstrates variation with the alteration of the superconducting order parameter. Moreover,...
Domain-like magnetic structure in superconductors of ErRh4 B4 and HoMo6S8 type
The problem of the coexistence of superconductivity and magnetic order is studied by taking into account the indirect exchange interaction, magnetic dipolar interaction and magnetic anisotropy. It is shown that the domain-like magnetic structure should be realized in the superconducting phases of ErRh4B4 and HoMo6S8 at the temperatures Tm= 1.4 and 0.7 K respectively. The transition from superconducting domain-like phase (DS) to the normal ferromagnetic (FN) state is described.
We investigate the properties of the inhomogeneous domain-type magnetic structure (DS phase) produced in magnetic superconductors such as HoMo,S, in the region where superconductivity and magnetism coexist. We show that the superconducting critical current in the DS phase decreases to zero when the temperature is lowered to T $ (the supercooling temperature of the D S phase). The wave vector of the magnetic structure decreases at the same time with increasing current flowing through the sample. We investigate the behavior of the DS in a magnetic field, obtain the phase diagram in the (H,T) plane. In the region where the field penetrates, the DSphase is substantially altered: new peaks 2nQ (n is an integer) appear in the neutron scattering, and the wave vector Q decreases with increasing field.
Point contact spectroscopy on the ferromagnetic superconductor HoMo6S8
Physica B: Condensed Matter, 1996
Point contact spectroscopy performed in single crystals of the ferromagnetic superconductor HoMoGSs, has been used to study the evolution in temperature and competition of the two order parameters. At temperatures of the order of the superconducting transition, we observe the onset of a structure in the d V/dI versus V characteristics that may be related to the development of the superconducting energy gap. At temperatures close to the ferromagnetic transitions, we also observe the growth of another structure in the dV/dIversus V characteristics that may be correlated with the development of the magnetic order parameter. This feature in the d~?dI versus V characteristic develops in a direction opposite to the structure associated with the superconducting energy gap.
Solid State Communications, 1985
In the framework of Ising ferromagnetic model the temperature dependence of the domain wall surface energy is studied. The obtained results are used to calculate the temperature dependence of the wave vector of the oscillatory magnetic structure in the coexistence phase of ferromagnetic superconductor HoMo6Ses. The estimate of the exchange interaction of localized moments and electrons explains why the coexistence phase survives on cooling down to zero temperature in HoMo6 Se8 while the reentrant transition into the normal ferromagnetic phase takes place in HoMod Se8 .
Magnetic superconductors of HoMo 6 S 8 type: The effect of magnetic field and supercurrent
We study the magnetic superconductors for which the second order phase transition to the ferro-magnetic state would take place at the temperature Bc < T,r if the superconductivity was absent. In this case the inhomogeneous magnetic structure of domain-like type (DS phase) appears in superconductors below TM = BC. The effect of the magnetic field H on DS phase is analysed and the region of DS phase existence in the plane (H, T) is found. The new peaks 2nQ (n is integer) should appear in the neutron scattering in the presence of the magnetic field. The wavevector Q of magnetic structure decreases with the growth of magnetic field or supercurrent.
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arXiv (Cornell University), 2022
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Magnetic field dependence of the effective penetration depth (l) determined by mSR is reported for 1H-CaðAl 0:5 Si 0:5 Þ 2 , a structurally new phase of CaðAl 0:5 Si 0:5 Þ 2 . The new phase has an AlB 2 -type crystal structure with P3 symmetry which, in contrast to earlier reports, does not exhibit superlattice structure along the c-axis. The bulk susceptibility measurement indicates that the upper critical field is much lower than that in superstructured ones for both c-and a-axis directions. A weak anisotropy in the superconducting order parameter is suggested from the increase of l with increasing external field. r
TOPICAL REVIEW: Magnetism in Fe-based superconductors
J Phys Condens Matter, 2010
In this review, we present a summary of experimental studies of magnetism in Fe-based superconductors. The doping dependent phase diagram shows strong similarities to the generic phase diagram of the cuprates. Parent compounds exhibit magnetic order together with a structural phase transition both of which are progressively suppressed with doping allowing superconductivity to emerge. The stripe-like spin arrangement of Fe moments in the magnetically ordered state shows the identical in-plane structure for the RFeAsO (R=rare earth) and AFe 2 As 2 (A=Sr, Ca, Ba, Eu and K) parent compounds, notably different than the spin configuration of the cuprates. Interestingly, Fe 1+y Te orders with a different spin order despite very similar Fermi surface topology. Studies of the spin dynamics in the parent compounds shows that the interactions are best characterized as anisotropic three-dimensional (3D) interactions. Despite the room temperature tetragonal structure, analysis of the low temperature spin waves under the assumption of a Heisenberg Hamiltonian indicates strong in-plane anisotropy with a significant next-near neighbor interaction. In the superconducting state, a resonance, localized in both wavevector and energy is observed in the spin excitation spectrum as in the cuprates. This resonance is observed at a wavevector compatible with a Fermi surface nesting instability independent of the magnetic ordering of the relevant parent compound. The resonance energy (E r) scales with superconducting transition temperature (T C) as E r ∼4.9 k B T C consistent with the canonical value of ∼5 k B T C observed in the cuprates. Moreover, the relationship between the resonance energy and the superconducting gap, ∆, is similar to that observed in many unconventional superconductors (E r /2∆ ∼ 0.64). Material Max. T C (K) LaFeAsO 1−x F x [1] 26 NdFeAsO 1−x F x [2] 52 PrFeAsO 1−x F x [3] 52 SmFeAsO 1−x F x [4] 55 CeFeAsO 1−x F x [5] 41 GdFeAsO 1−x F x [7] 50 TbFeAsO 1−x F x [9] 46 DyFeAsO 1−x F x [9] 45 Gd 1−x Th x FeAsO [10] 56 LaFeAsO 1−y [11, 12] 28 NdFeAsO 1−y [11, 12, 13] 53 PrFeAsO 1−y [11, 12] 48 SmFeAsO 1−y [11] 55 GdFeAsO 1−y [14, 12] 53 TbFeAsO 1−y [12] 52 DyFeAsO 1−y [12] 52 LaFe 1−x Co x AsO [17] 14 SmFe 1−x Ni x AsO [26] 10 SmFe 1−x Co x AsO [27] 15 LaFe 1−x Ir x AsO [28] 12 Material Max. T C (K) Ba 1−x K x Fe 2 As 2 [16] 38 Ba 1−x Rb x Fe 2 As 2 [29] 23 K 1−x Sr x Fe 2 As 2 [30] 36 Cs 1−x Sr x Fe 2 As 2 [30] 37 Ca 1−x Na x Fe 2 As 2 [31] 20 Eu 1−x K x Fe 2 As 2 [32] 32 Eu 1−x Na x Fe 2 As 2 [33] 35 Ba(Fe 1−x Co x) 2 As 2 [18, 34] 22-24 Ba(Fe 1−x Ni x) 2 As 2 [19] 20 Sr(Fe 1−x Ni x) 2 As 2 [35] 10 Ca(Fe 1−x Co x) 2 As 2 [36] 17 Ba(Fe 1−x Rh x) 2 As 2 [20] 24 Ba(Fe 1−x Pd x) 2 As 2 [20] 19 Sr(Fe 1−x Rh x) 2 As 2 [21] 22 Sr(Fe 1−x Ir x) 2 As 2 [21] 22 Sr(Fe 1−x Pd x) 2 As 2 [21] 9 Ba(Fe 1−x Ru x) 2 As 2 [22] 21 Sr(Fe 1−x Ru x) 2 As 2 [23] 13.5 LiFeAs [37, 38, 39] 18 Na 1−x FeAs [40] 25 Fe 1+y Se x Te 1−x [41] 15