اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدSuperconductivity induced by ruthenium substitution in an iron arsenide: investigation of SrFe2-xRuxAs2 (0 <= x <= 2)
42
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
The magnetism in SrFe2As2 can be suppressed by electron doping through a small substitution of Fe by Co or Ni, giving way to superconductivity. We demonstrate that a massive substitution of Fe by isovalent ruthenium similarly suppresses the magnetic ordering in SrFe2-xRuxAs2 and leads to bulk superconductivity for 0.6 <= x <= 0.8. Magnetization, electrical resistivity, and specific heat data show Tc up to approx 20K. Detailed structural investigations reveal a strong decrease of the lattice parameter ratio c/a with increasing x. DFT band structure calculations are in line with the observation that the magnetic order in SrFe2-xRuxAs2 is only destabilized for large x.
قيم البحث
اقرأ أيضاً
In the electron doped compounds SrFe_(2-x)Co_xAs_2 superconductivity with T_c up to 20 K is observed for 0.2 < x < 0.4. Results of structure determination, magnetic susceptibility, electrical resistivity, and specific heat are reported. The observati
on of bulk superconductivity in all thermodynamic properties -- despite strong disorder in the Fe-As layer -- favors an itinerant picture in contrast to the cuprates and renders a p- or d-wave scenario unlikely. DFT calculations find that the substitution of Fe by Co (x > 0.3) leads to the suppression of the magnetic ordering present in SrFe_2As_2 due to a rigid down-shift of the Fe-3d_(x^2-y^2) related band edge in the density of states.
The effect of pressure on superconductivity of 111 type NaxFeAs is investigated through temperature dependent electrical resistance measurement in a diamond anvil cell. The superconducting transition temperature (Tc) increases from 26 K to a maximum
31 K as the pressure increases from ambient to 3 GPa. Further increasing pressure suppresses Tc drastically. The behavior of pressure tuned Tc in NaxFeAs is much different from that in LixFeAs, although they have the same Cu2Sb type structure
We investigate the chemical substitution of group 5 into BaFe2As2 (122) iron arsenide, in the effort to understand why Fe-site hole doping of this compound (e.g., using group 5 or 6) does not yield bulk superconductivity. We find an increase in c-lat
tice parameter of the BaFe2As2 with the substitution of V, Nb, or Ta; the reduction in c predicts the lack of bulk superconductivity [1] that is confirmed here through transport and magnetization results. However, our spectroscopy measurements find a coexistence of antiferromagnetic and local superconducting nanoscale regions in V-122, observed for the first time in a transition-metal hole-doped iron arsenide. In BaFe2As2, there is a complex connection between local parameters such as composition and lattice strain, average lattice details, and the emergence of bulk quantum states such as superconductivity and magnetism. [1] L. M. N. Konzen, and A. S. Sefat, J. Phys.: Condens. Matter 29 (2017), 083001.
Platelet-like single crystals of the Ca(Fe1-xCox)2As2 series having lateral dimensions up to 15 mm and thickness up to 0.5 mm were obtained from the high temperature solution growth technique using Sn flux. Upon Co doping, the c-axis of the tetragona
l unit cell decreases, while the a-axis shows a less significant variation. Pristine CaFe2As2 shows a combined spin-density-wave and structural transition near T = 166 K which gradually shifts to lower temperatures and splits with increasing Co-doping. Both transitions terminate abruptly at a critical Co-concentration of xc = 0.075. For x geq 0.05, superconductivity appears at low temperatures with a maximum transition temperature TC of around 20 K. The superconducting volume fraction increases with Co concentration up to x = 0.09 followed by a gradual decrease with further increase of the doping level. The electronic phase diagram of Ca(Fe1-xCox)2As2 (0 leq x leq 0.2) series is constructed from the magnetization and electric resistivity data. We show that the low-temperature superconducting properties of Co-doped CaFe2As2 differ considerably from those of BaFe2As2 reported previously. These differences seem to be related to the extreme pressure sensitivity of CaFe2As2 relative to its Ba counterpart.
EuFe2As2 is a member of the ternary iron arsenide family. Similar to BaFe2As2 and SrFe2As2, EuFe2As2 exhibits a clear anomaly in resistivity near 200 K. It suggests that EuFe2As2 is another promising parent compound in which superconductivity may be
realized by appropriate doping. Here we report the discovery of superconductivity in Eu0.7Na0.3Fe2As2 by partial substitution of the europium site with sodium. ThCr2Si2 tetragonal structure, as expected for EuFe2As2, is formed as the main phase for the composition Eu0.7Na0.3Fe2As2. Resistivity measurement reveals a transition temperature as high as 34.7 K in this compound, which is higher than the Tc of Eu0.5K0.5Fe2As2.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
