Nonmagnetic ground state in the molecular material Nd2[Cu (pba)]3 -23 H2O (pba = 1,3-propylenebis( oxamato ))

Olivier Kahn (1, 2) , Robert Oushoorn (1, 2) , Olivier Guillou (1, 2) , Marc Drillon (3) , Pierre Rabu (3) , Kamal Boubekeur (4) , Patrick Batail (4)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
2 Laboratoire de Chimie Inorganique
3 IPCMS - Institut de Physique et Chimie des Matériaux de Strasbourg
4 laboratoire de physique du Solide

The crystal structure of Nd 2 [Cu{pba)b•23 H 2 O with pba= 1,3-propylenebis(oxamato) was first described two years aga. lt consists of tube-like motifs of the formula Nd 2 [Cu(pba)b{H 2 O) 9 and noncoordinated water molecules. Each Nd(III) ion is surrounded by three nearest-neighbor Cu(II) ions, and in turn each Cu(II) ion_is situated between two Nd(III) ions. The magnetic properties of the compound have been investigated. The magnetic susceptibility presents a rounded maximum around 2.5 K, and the product of the magnetic susceptibility and the temperature tends to zero as the temperature approaches absolute zero. This indicates that the ground state of the compound is quasinonmagnetic, which at a first view is quite an unexpected result. This situation is attributed to a compensation between the local magnetic moments of the two Nd(III) ions and the three Cu(III) ions at low temperature. This idea has been tested with a theoretical model in which the local Kramer's doublets for Nd(III) and Cu(II) interact antiferromagnetically. A compensation of the magnetic moments may be expected for a value of the ratio g d /9c u close to 1.73 g d and 9cu being the average values of the Zeeman factor for the ground Kramer's doublet of Nd(III) and Cu(II), respectively.

Domaines: Matériaux

Olivier Kahn, Robert Oushoorn, Olivier Guillou, Marc Drillon, Pierre Rabu, et al.. Nonmagnetic ground state in the molecular material Nd2[Cu (pba)]3 -23 H2O (pba = 1,3-propylenebis( oxamato )). New Journal of Chemistry, 1995, 19 (5-6), pp.655-660. ⟨hal-04207378⟩