Highly unquenched orbital moment in Fe phthalocyanine
Close
Articolul precedent
Articolul urmator
657 1
Ultima descărcare din IBN:
2021-09-28 10:46
SM ISO690:2012
BARTOLOME, Juan. Highly unquenched orbital moment in Fe phthalocyanine. In: Physical Methods in Coordination and Supramolecular Chemistry, 24-26 octombrie 2012, Chişinău. Chisinau, Republic of Moldova: 2012, XVII, p. 10.
EXPORT metadate:
Google Scholar
Crossref
CERIF

DataCite
Dublin Core
Physical Methods in Coordination and Supramolecular Chemistry
XVII, 2012
Conferința ""Physical Methods in Coordination and Supramolecular Chemistry""
Chişinău, Moldova, 24-26 octombrie 2012

Highly unquenched orbital moment in Fe phthalocyanine


Pag. 10-10

Bartolome Juan
 
Instituto de Ciencia de Materiales, CSIC
 
 
Disponibil în IBN: 26 mai 2020


Rezumat

Metal-Phthalocyanine molecules (MPc) form a family of compounds with a wide range of commercial application such as catalysts or dyes, and more recently in thin film technology. Among them iron(II) phthalocyanine (FePc) has received increasing attention because of their similarity to (haem) proteins. In an e -phase of FePc, where the FePc molecules are stacked in a herringbone structure, the Fe atoms are strongly magnetically coupled into ferromagnetic Ising chains with very weak antiferromagnetic interchain coupling. The chains achieve 3D long range ordering at TN=10 K, and strong irreversibility (slow relaxation) below 5K. By 57Fe Mössbauer spectroscopy we could ascertain that the Fe(II) is in a S=1 state and the hyperfine field in the ordered phase reached the value of Bhf=66.2 T, a record value in Fe(II). The low temperature relaxational behaviour could be explained as due to soliton domain wall motion, with an activation energy of Ea/kB=72 K. The large, and positive hyperfine field could only be explained if there were a large orbital component in the magnetic moment. This large, unquenched orbital moment has been measured directly in a X-ray Magnetic Circular Dichroism (XMCD) spectroscopic study on FePc thin films deposited parallelly on a Au surface predeposited on a Si substrate. The XMCD spectra at the L3 and L2 Applying the sum rule analysis the values for the orbital and spin moment components  mL and  mS , and the intra-atomic magnetic dipolar components  mT were obtained. The orbital moment is L B m  0.53 0.04 and the isotropic spin component is S B m  0.64  0.05 . The origin of this unusually high orbital moment is the incompletely filled eg level lying close to the Fermi energy. The ferromagnetically coupled Fe moments show strong, in-plane anisotropy; i.e. parallel to the FePc molecule [1]. Angular dependent measurements at the Fe K-edge also show strong quadrupolar excitations associated to a strong orbital moment, confirming the above result of the existence of a large, unquenched orbital moment in this molecule.