High relaxation barrier in neodymium furoate-based field-induced SMMs
Bartolomé, E. ; Arauzo, A. (Universidad de Zaragoza) ; Luzón, J. ; Melnic, S. ; Shova, S. ; Prodius, D. ; Nlebedim, I. C. ; Bartolomé, F. (Universidad de Zaragoza) ; Bartolomé, J.
Resumen: Two new neodymium molecular magnets of formula {Nd(a-fur)3(H2O)2]·DMF}n (1) and {Nd0.065La0.935(a-fur)3(H2O)2]}n (2), a-fur = C4H3OCOO, have been synthesized. In (1) the furoate ligands, in bidentate bridging mode, consolidate zig-zag chains running along the a-direction. Compound (2) is a magnetically diluted complex of a polymeric chain along the b-axis. Heat capacity, dc magnetization and ac susceptibility measurements have been performed from 1.8 K up to room temperature. Ab initio calculations yielded the gyromagnetic factors gx* = 0.52, gy* = 1.03, gz* = 4.41 for (1) and gx* = 1.35, gy* = 1.98, gz* = 3.88 for (2), and predicted energy gaps of ¿/kB = 125.5 K (1) and ¿/kB = 58.8 K (2). Heat capacity and magnetometry measurements agree with these predictions, and confirm the non-negligible transversal anisotropy of the Kramers doublet ground state. A weak intrachain antiferromagnetic interaction J'/kB = -3.15 × 10-3 K was found for (1). No slow relaxation is observed at H = 0, attributed to the sizable transverse anisotropy component, and/or dipolar or exchange interactions enhancing the quantum tunnelling probability. Under an external applied field as small as 80 Oe, two slow relaxation processes appear: above 3 K the first relaxation mechanism is associated to a combination of Orbach process, with a sizeable activation energy U/kB = 121 K at 1.2 kOe for (1), Raman and direct processes; the second, slowest relaxation mechanism is associated to a direct process, affected by phonon-bottleneck effect. For complex (2) a smaller U/kB = 61 K at 1.2 kOe is found, together with larger g*-transversal terms, and the low-frequency process is quenched. The reported complexes represent rare polymeric Nd single-ion magnets exhibiting high activation energies among the scarce Nd(iii) family. © 2019 The Royal Society of Chemistry.
Idioma: Inglés
DOI: 10.1039/c9dt02047k
Año: 2019
Publicado en: Dalton Transactions 48, 41 (2019), 15386-15396
ISSN: 1477-9226
Factor impacto JCR: 4.174 (2019)
Categ. JCR: CHEMISTRY, INORGANIC & NUCLEAR rank: 5 / 45 = 0.111 (2019) - Q1 - T1
Factor impacto SCIMAGO: 1.048 - Inorganic Chemistry (Q1)
Financiación: info:eu-repo/grantAgreement/ES/DGA/E12-R17
Financiación: info:eu-repo/grantAgreement/ES/MINECO/MAT2017-83468-R
Tipo y forma: Article (Published version)
Área (Departamento): Área Física Materia Condensada (Dpto. Física Materia Condensa.)
You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. You may not use the material for commercial purposes.
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Idioma: Inglés
DOI: 10.1039/c9dt02047k
Año: 2019
Publicado en: Dalton Transactions 48, 41 (2019), 15386-15396
ISSN: 1477-9226
Factor impacto JCR: 4.174 (2019)
Categ. JCR: CHEMISTRY, INORGANIC & NUCLEAR rank: 5 / 45 = 0.111 (2019) - Q1 - T1
Factor impacto SCIMAGO: 1.048 - Inorganic Chemistry (Q1)
Financiación: info:eu-repo/grantAgreement/ES/DGA/E12-R17
Financiación: info:eu-repo/grantAgreement/ES/MINECO/MAT2017-83468-R
Tipo y forma: Article (Published version)
Área (Departamento): Área Física Materia Condensada (Dpto. Física Materia Condensa.)
You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. You may not use the material for commercial purposes. Exportado de SIDERAL (2025-01-27-14:42:53)
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