title: XMCD for monitoring exchange interactions. The role of the Gd 4f and 5d orbitals in metal-nitronyl nitroxide magnetic chains.
abstract: We report here the X-ray magnetic circular dichroism (XMCD) study at the Gd M(4,5)- and L(2,3)-edges of two linear magnetic chains involving Gd(III) cations bridged by nitronyl nitroxide radicals. This spectroscopy directly probes the magnetic moments of the 4f and 5d orbitals of the gadolinium ions. We compare macroscopic magnetic measurements and local XMCD signals. The M(4,5)-edges results are in agreement with the J values extracted from the fits of the SQUID magnetic measurements. The L(2,3)-edges signals show that the electronic density in the Gd 5d orbitals depends on the neighbors of the gadolinium cations. Nevertheless, the 5d orbitals do not seem to play any role in the superexchange pathway between radicals through the metal ion proposed to explain the particular magnetic exchange interactions between the radicals in these chains.
authors.affiliation: Laboratoire de Chimie Inorganique et Matériaux Moléculaires, Université Pierre et Marie Curie, Bât. F74, Case 42, 4 place jussieu, 75252 Paris Cedex 05, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Champion
authors.forename: Nikolia
authors.initials: N
authors.lastname: Lalioti
authors.forename: Vassilis
authors.initials: V
authors.lastname: Tangoulis
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: Arrio
authors.forename: Philippe
authors.initials: P
authors.lastname: Sainctavit
authors.forename: Françoise
authors.initials: F
authors.lastname: Villain
authors.forename: Andrea
authors.initials: A
authors.lastname: Caneschi
authors.forename: Dante
authors.initials: D
authors.lastname: Gatteschi
authors.forename: Christine
authors.initials: C
authors.lastname: Giorgetti
authors.forename: François
authors.initials: F
authors.lastname: Baudelet
authors.forename: Michel
authors.initials: M
authors.lastname: Verdaguer
authors.forename: Christophe
authors.initials: C
authors.lastname: Cartier dit Moulin