scholarly journals Kondo Effect in Unconventional Superconductors

2002 ◽  
Vol 71 (Suppl) ◽  
pp. 231-233 ◽  
Author(s):  
Masashige Matsumoto ◽  
Mikito Koga
Keyword(s):  
Kondo Effect ◽  
Unconventional Superconductors

KONDO EFFECT AND LOCALIZED SPIN FLUCTUATIONS IN THE Zn-TRANSITION METAL SYSTEM

1971 ◽  
Vol 32 (C1) ◽  
pp. C1-221-C1-223
Author(s):  
P. J. FORD ◽  
C. RIZZUTO ◽  
E. SALAMONI ◽  
P. ZANI
Keyword(s):  
Transition Metal ◽  
Kondo Effect ◽  
Spin Fluctuations ◽  
Metal System ◽  
Transition Metal System

MÖSSBAUER RELAXATION MEASUREMENTS ON Yb IN LaBel3 : INFLUENCE OF KONDO EFFECT AND SUPERCONDUCTIVITY

1988 ◽  
Vol 49 (C8) ◽  
pp. C8-729-C8-730 ◽  
Author(s):  
P. Bonville ◽  
P. Imbert ◽  
G. Jéhanno ◽  
F. Gonzalez-Jimenez
Keyword(s):  
Kondo Effect ◽  
Relaxation Measurements

scholarly journals Renormalization of spin excitations and Kondo effect in open-shell nanographenes

2021 ◽  
Vol 104 (7) ◽  
Author(s):  
David Jacob ◽  
Ricardo Ortiz ◽  
Joaquín Fernández-Rossier
Keyword(s):  
Kondo Effect ◽  
Open Shell ◽  
Spin Excitations

Weak Kondo effect in the monocrystalline transition metal dichalcogenide ZrTe2

2021 ◽  
Vol 103 (17) ◽  
Author(s):  
Yihao Wang ◽  
Changzheng Xie ◽  
Junbo Li ◽  
Zan Du ◽  
Liang Cao ◽  
...  
Keyword(s):  
Transition Metal ◽  
Kondo Effect ◽  
Transition Metal Dichalcogenide

scholarly journals Intrinsically weak magnetic anisotropy of cerium in potential hard-magnetic intermetallics

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Anna Galler ◽  
Semih Ener ◽  
Fernando Maccari ◽  
Imants Dirba ◽  
Konstantin P. Skokov ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Magnetic Anisotropy ◽  
High Performance ◽  
Kondo Effect ◽  
Quantitative Description ◽  
Many Body ◽  
Heavy Rare Earth Elements ◽  
Fe Intermetallics ◽  
Full Temperature

AbstractCerium-based intermetallics are currently attracting much interest as a possible alternative to existing high-performance magnets containing scarce heavy rare-earth elements. However, the intrinsic magnetic properties of Ce in these systems are poorly understood due to the difficulty of a quantitative description of the Kondo effect, a many-body phenomenon where conduction electrons screen out the Ce-4f moment. Here, we show that the Ce-4f shell in Ce–Fe intermetallics is partially Kondo screened. The Kondo scale is dramatically enhanced by nitrogen interstitials suppressing the Ce-4f contribution to the magnetic anisotropy, in striking contrast to the effect of nitrogenation in isostructural intermetallics containing other rare-earth elements. We determine the full temperature dependence of the Ce-4f single-ion anisotropy and show that even unscreened Ce-4f moments contribute little to the room-temperature intrinsic magnetic hardness. Our study thus establishes fundamental constraints on the potential of cerium-based permanent magnet intermetallics.

scholarly journals Kondo effect and superconductivity in niobium with iron impurities

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hansong Zeng ◽  
Dan Zhou ◽  
Guoqing Liang ◽  
Rujun Tang ◽  
Zhi H. Hang ◽  
...  
Keyword(s):  
Magnetic Moment ◽  
Low Temperatures ◽  
Kondo Effect ◽  
Film Structure ◽  
Kondo Temperature ◽  
Superconducting Transition ◽  
Interesting Phenomenon ◽  
Superconducting Device ◽  
Bcc Lattice ◽  
Device Applications

AbstractKondo effect is an interesting phenomenon in quantum many-body physics. Niobium (Nb) is a conventional superconductor important for many superconducting device applications. It was long thought that the Kondo effect cannot be observed in Nb because the magnetic moment of a magnetic impurity, e.g. iron (Fe), would have been quenched in Nb. Here we report an observation of the Kondo effect in a Nb thin film structure. We found that by co-annealing Nb films with Fe in Argon gas at above 400 $$^{\circ }$$ ∘ C for an hour, one can induce a Kondo effect in Nb. The Kondo effect is more pronounced at higher annealing temperature. The temperature dependence of the resistance suggests existence of remnant superconductivity at low temperatures even though the system never becomes superconducting. We find that the Hamann theory for the Kondo resistivity gives a satisfactory fitting to the result. The Hamann analysis gives a Kondo temperature for this Nb–Fe system at $$\sim $$ ∼ 16 K, well above the superconducting transition onset temperature 9 K of the starting Nb film, suggesting that the screening of the impurity spins is effective to allow Cooper pairs to form at low temperatures. We suggest that the mechanism by which the Fe impurities retain partially their magnetic moment is that they are located at the grain boundaries, not fully dissolved into the bcc lattice of Nb.

scholarly journals Multiplicity, Parity and Angular Momentum of a Cooper Pair in Unconventional Superconductors of D4h Symmetry: Sr2RuO4 and Fe-Pnictide Materials

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1435
Author(s):  
Victor G. Yarzhemsky
Keyword(s):  
Angular Momentum ◽  
Cooper Pair ◽  
Point Group ◽  
Group Symmetry ◽  
Cooper Pairs ◽  
Group Approach ◽  
Angular Momentum Projection ◽  
Space Group ◽  
Unconventional Superconductors ◽  
Even Pairs

Sr2RuO4 and Fe-pnictide superconductors belong to the same point group symmetry D4h. Many experimental data confirm odd pairs in Sr2RuO4 and even pairs in Fe-pnictides, but opposite conclusions also exist. Recent NMR results of Pustogow et al., which revealed even Cooper pairs in Sr2RuO4, require reconsideration of symmetry treatment of its SOP (superconducting order parameter). In the present work making use of the Mackey–Bradley theorem on symmetrized squares, a group theoretical investigation of possible pairing states in D4h symmetry is performed. It is obtained for I4/mmm , i.e., space group of Sr2RuO4, that triplet pairs with even spatial parts are possible in kz direction and in points M and Y. For the two latter cases pairing of equivalent electrons with nonzero total momentum is proposed. In P4/nmm space group of Fe- pnictides in point M, even and odd pairs are possible for singlet and triplet cases. It it shown that even and odd chiral states with angular momentum projection m=±1 have nodes in vertical planes, but Eg is nodal , whereas Eu is nodeless in the basal plane. It is also shown that the widely accepted assertion that the parity of angular momentum value is directly connected with the spatial parity of a pair is not valid in a space-group approach to the wavefunction of a Cooper pair.

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