Unusual superconductivity in crystallographically disordered RT2−xSn2 compounds

Alessia Provino; Volodymyr Smetana; Vitalii Shtender; Stefanie Siebeneichler; Marina Putti; Alexandra Franz; Carlo Ferdeghini; Vitalij K. Pecharsky; Anja Verena Mudring; Pietro Manfrinetti

doi:10.1016/j.jallcom.2024.175025

Unusual superconductivity in crystallographically disordered RT_2−xSn₂ compounds

Alessia Provino, Volodymyr Smetana, Vitalii Shtender, Stefanie Siebeneichler, Marina Putti, Alexandra Franz, Carlo Ferdeghini, Vitalij K. Pecharsky, Anja Verena Mudring, Pietro Manfrinetti^*

^*Corresponding author af dette arbejde

Publikation: Bidrag til tidsskrift/Konferencebidrag i tidsskrift /Bidrag til avis › Tidsskriftartikel › Forskning › peer review

Abstract

The discovery of new superconducting materials represents a complementary and crucial tile to shed light on the mechanism controlling the phenomenon of superconductivity. During the search for new superconducting materials, we discovered a new series of intermetallic compounds with the general composition RZn_2−xSn₂ (R = La, Ce, Pr, Nd). Their formation and crystal structure have been investigated. The Zn content decreases along the series from ≈ 1.50 in LaZn_1.50(1)Sn_1.98(2) to ≈ 1.32 in NdZn_1.321(8)Sn_2.01(2), due to the partial occupation of one of the two Zn sites [the Zn1 (2c) site, which from ≈ 50% in the La compound drops to ≈ 42%, ≈ 37% and ≈ 32% in the Ce, Pr and Nd compounds, respectively]. Both the Zn occupation factor and unit cell volume follow the lanthanide contraction. No such compound has been observed with Sm. AC and DC magnetic susceptibility and transport measurements revealed LaZn_1.5Sn₂ to undergo a sharp superconducting transition at T_c = 5.5 K. In order to search for further possible superconductive homologues, the lanthanum substituted phases La(Zn,T)_2–xSn₂ (T = Ti, Mn, Fe, Co, Ni, Cu, Pd, Ag, Pt, Au, Cd; x ≈ 0.5) were also prepared. The crystal structure of the ternary compounds is a disordered defective derivative of the tetragonal CaBe₂Ge₂-type (tP10, P4/nmm), with a partially occupied Zn Wyckoff site and a disordered Sn position. Three related isostructural series, corresponding to three new prototypes, have been identified; they all contain conventional checkered pyramidal layers characteristic of the archetype. The magnetic and transport properties have been measured for some of these substituted quaternary La compounds and we found that superconductivity is preserved in them but in the orthorhombic compounds or when T was a magnetic transition metal (e.g., Ni or Mn). A slight decrease in T_c down to about 4.0 K was detected as a result of the Zn by T atomic substitution.

Originalsprog	Engelsk
Artikelnummer	175025
Tidsskrift	Journal of Alloys and Compounds
Vol/bind	1000
ISSN	0925-8388
DOI	https://doi.org/10.1016/j.jallcom.2024.175025
Status	Udgivet - sep. 2024

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10.1016/j.jallcom.2024.175025

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@article{a5b143049d5b49b8bae37fe719e7a17d,

title = "Unusual superconductivity in crystallographically disordered RT2−xSn2 compounds",

abstract = "The discovery of new superconducting materials represents a complementary and crucial tile to shed light on the mechanism controlling the phenomenon of superconductivity. During the search for new superconducting materials, we discovered a new series of intermetallic compounds with the general composition RZn2−xSn2 (R = La, Ce, Pr, Nd). Their formation and crystal structure have been investigated. The Zn content decreases along the series from ≈ 1.50 in LaZn1.50(1)Sn1.98(2) to ≈ 1.32 in NdZn1.321(8)Sn2.01(2), due to the partial occupation of one of the two Zn sites [the Zn1 (2c) site, which from ≈ 50% in the La compound drops to ≈ 42%, ≈ 37% and ≈ 32% in the Ce, Pr and Nd compounds, respectively]. Both the Zn occupation factor and unit cell volume follow the lanthanide contraction. No such compound has been observed with Sm. AC and DC magnetic susceptibility and transport measurements revealed LaZn1.5Sn2 to undergo a sharp superconducting transition at Tc = 5.5 K. In order to search for further possible superconductive homologues, the lanthanum substituted phases La(Zn,T)2–xSn2 (T = Ti, Mn, Fe, Co, Ni, Cu, Pd, Ag, Pt, Au, Cd; x ≈ 0.5) were also prepared. The crystal structure of the ternary compounds is a disordered defective derivative of the tetragonal CaBe2Ge2-type (tP10, P4/nmm), with a partially occupied Zn Wyckoff site and a disordered Sn position. Three related isostructural series, corresponding to three new prototypes, have been identified; they all contain conventional checkered pyramidal layers characteristic of the archetype. The magnetic and transport properties have been measured for some of these substituted quaternary La compounds and we found that superconductivity is preserved in them but in the orthorhombic compounds or when T was a magnetic transition metal (e.g., Ni or Mn). A slight decrease in Tc down to about 4.0 K was detected as a result of the Zn by T atomic substitution.",

keywords = "Crystal structure, Electronic structure, Rare earth stannides, Rare-earth ternary intermetallics, RZnSn compounds, Superconductivity",

author = "Alessia Provino and Volodymyr Smetana and Vitalii Shtender and Stefanie Siebeneichler and Marina Putti and Alexandra Franz and Carlo Ferdeghini and Pecharsky, {Vitalij K.} and Mudring, {Anja Verena} and Pietro Manfrinetti",

note = "Publisher Copyright: {\textcopyright} 2024 The Authors",

year = "2024",

month = sep,

doi = "10.1016/j.jallcom.2024.175025",

language = "English",

volume = "1000",

journal = "Journal of Alloys and Compounds",

issn = "0925-8388",

publisher = "Elsevier B.V.",

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TY - JOUR

T1 - Unusual superconductivity in crystallographically disordered RT2−xSn2 compounds

AU - Provino, Alessia

AU - Smetana, Volodymyr

AU - Shtender, Vitalii

AU - Siebeneichler, Stefanie

AU - Putti, Marina

AU - Franz, Alexandra

AU - Ferdeghini, Carlo

AU - Pecharsky, Vitalij K.

AU - Mudring, Anja Verena

AU - Manfrinetti, Pietro

PY - 2024/9

Y1 - 2024/9

N2 - The discovery of new superconducting materials represents a complementary and crucial tile to shed light on the mechanism controlling the phenomenon of superconductivity. During the search for new superconducting materials, we discovered a new series of intermetallic compounds with the general composition RZn2−xSn2 (R = La, Ce, Pr, Nd). Their formation and crystal structure have been investigated. The Zn content decreases along the series from ≈ 1.50 in LaZn1.50(1)Sn1.98(2) to ≈ 1.32 in NdZn1.321(8)Sn2.01(2), due to the partial occupation of one of the two Zn sites [the Zn1 (2c) site, which from ≈ 50% in the La compound drops to ≈ 42%, ≈ 37% and ≈ 32% in the Ce, Pr and Nd compounds, respectively]. Both the Zn occupation factor and unit cell volume follow the lanthanide contraction. No such compound has been observed with Sm. AC and DC magnetic susceptibility and transport measurements revealed LaZn1.5Sn2 to undergo a sharp superconducting transition at Tc = 5.5 K. In order to search for further possible superconductive homologues, the lanthanum substituted phases La(Zn,T)2–xSn2 (T = Ti, Mn, Fe, Co, Ni, Cu, Pd, Ag, Pt, Au, Cd; x ≈ 0.5) were also prepared. The crystal structure of the ternary compounds is a disordered defective derivative of the tetragonal CaBe2Ge2-type (tP10, P4/nmm), with a partially occupied Zn Wyckoff site and a disordered Sn position. Three related isostructural series, corresponding to three new prototypes, have been identified; they all contain conventional checkered pyramidal layers characteristic of the archetype. The magnetic and transport properties have been measured for some of these substituted quaternary La compounds and we found that superconductivity is preserved in them but in the orthorhombic compounds or when T was a magnetic transition metal (e.g., Ni or Mn). A slight decrease in Tc down to about 4.0 K was detected as a result of the Zn by T atomic substitution.

AB - The discovery of new superconducting materials represents a complementary and crucial tile to shed light on the mechanism controlling the phenomenon of superconductivity. During the search for new superconducting materials, we discovered a new series of intermetallic compounds with the general composition RZn2−xSn2 (R = La, Ce, Pr, Nd). Their formation and crystal structure have been investigated. The Zn content decreases along the series from ≈ 1.50 in LaZn1.50(1)Sn1.98(2) to ≈ 1.32 in NdZn1.321(8)Sn2.01(2), due to the partial occupation of one of the two Zn sites [the Zn1 (2c) site, which from ≈ 50% in the La compound drops to ≈ 42%, ≈ 37% and ≈ 32% in the Ce, Pr and Nd compounds, respectively]. Both the Zn occupation factor and unit cell volume follow the lanthanide contraction. No such compound has been observed with Sm. AC and DC magnetic susceptibility and transport measurements revealed LaZn1.5Sn2 to undergo a sharp superconducting transition at Tc = 5.5 K. In order to search for further possible superconductive homologues, the lanthanum substituted phases La(Zn,T)2–xSn2 (T = Ti, Mn, Fe, Co, Ni, Cu, Pd, Ag, Pt, Au, Cd; x ≈ 0.5) were also prepared. The crystal structure of the ternary compounds is a disordered defective derivative of the tetragonal CaBe2Ge2-type (tP10, P4/nmm), with a partially occupied Zn Wyckoff site and a disordered Sn position. Three related isostructural series, corresponding to three new prototypes, have been identified; they all contain conventional checkered pyramidal layers characteristic of the archetype. The magnetic and transport properties have been measured for some of these substituted quaternary La compounds and we found that superconductivity is preserved in them but in the orthorhombic compounds or when T was a magnetic transition metal (e.g., Ni or Mn). A slight decrease in Tc down to about 4.0 K was detected as a result of the Zn by T atomic substitution.

KW - Crystal structure

KW - Electronic structure

KW - Rare earth stannides

KW - Rare-earth ternary intermetallics

KW - RZnSn compounds

KW - Superconductivity

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U2 - 10.1016/j.jallcom.2024.175025

DO - 10.1016/j.jallcom.2024.175025

M3 - Journal article

AN - SCOPUS:85195466955

SN - 0925-8388

VL - 1000

JO - Journal of Alloys and Compounds

JF - Journal of Alloys and Compounds

M1 - 175025