Multifunktionale Einzelmolekülmagnete auf Lanthanoidbasis in neuem Licht

Abstract

D iese Autoren haben zu gleichen Teilen zu der Arbeit beigetragen.

A Theoretical Framework for Ratiometric Single Ion Luminescent Thermometers—Thermodynamic and Kinetic Guidelines for Optimized Performance

“…[159][160][161][162][163][164][165][166] More recent attempts reveal that lanthanides in mesoporous materials may be a promising addition to the field. [167][168][169][170] Usage of the lanthanides as luminescent ions even allows the combination of different functionalities such as luminescence thermometry and single-ion magnetism [171,172] or solid-state lighting. [173] Moreover, creative ways for novel alternative thermometry concepts using Boltzmann-based thermometry in the ground states have also been presented, which have the potential to strongly enhance relative sensitivities.…”

A Series of Rare‐Earth Mesoionic Carbene Complexes

“…There is a gradual reduction as the temperature approaches zero with the value settling at 8.15 cm 3 mol −1 K at 2 K. Magnetisation ( M ) vs. field ( H ) curves measured from 0–7 Tesla at 2 K and 4 K for 3Er rapidly saturate at values of ∼4.45 and ∼4.40 μ B mol −1 , respectively, confirming a well isolated ±15/2 ground state in both cases [12] . Similarly to 3Dy , in an applied 0.1 Tesla static field, 3Er exhibits temperature and frequency dependent behaviour characteristic of slow magnetic relaxation up to 12 K. Fitting of this data against a generalised Debye model gives a U eff barrier to the reversal of magnetisation of 127.98 K ( n =7.31, C =1.88×10 −5 s −1 K −n , τ 0 =7.66×10 −9 s), with the temperature dependence of the inverse relaxation time within the range 6–12 K indicative of both Raman and Orbach‐based relaxation processes being in operation, occurring via short‐lived virtual, as well as crystal‐field, excited states (τ −1 =τ 0 −1 exp [ U eff/kT] +CT n ), Figures 8,9,10 [23,24] …”

“…As the temperature approaches zero, the χ m T value settles on 11.26 cm 3 mol −1 K at 2 K. Magnetisation ( M ) vs. field ( H ) curves measured from 0–7 Tesla at 2 K and 4 K for 3Dy rapidly saturate at values of ∼5.20 and ∼5.10 μ B mol −1 , respectively, confirming a well isolated ±15/2 ground state in both cases [12] . In an applied 0.1 Tesla static field, 3Dy exhibits temperature and frequency dependent behaviour characteristic of slow magnetic relaxation up to 6.5 K. Fitting of this data against a generalised Debye model gives a U eff barrier to the reversal of magnetisation of 34.52 K ( n =6.91, C =2.45×10 −11 s −1 K −n , τ 0 =3.29×10 −6 s), with the temperature dependence of the inverse relaxation time within the range 2.5–6.5 K highlighting a dominant Orbach‐based relaxation mechanism via crystal‐field excited states (τ −1 =τ 0 −1 e [ U eff/kT] ), Figures 5,6,7 [23,24] . For comparison, the parent [Dy{N(SiMe 3 ) 2 } 3 ] complex exhibits no SMM‐type behaviour, with no out‐of‐phase peaks present in the presence of an AC field [25] .…”