title: Magnetic Structures of Heterometallic M(II)-M(III) Formate Compounds.
abstract: A study of the magnetic structure of the [NH2(CH3)2]n[FeIIIMII(HCOO)6]nniccolite-like compounds, with MII= CoII(2) and MnII(3) ions, has been carried out using neutron diffraction and compared with the previously reported FeII-containing compound (1). The inclusion of two different metallic atoms into the niccolite-like structure framework leads to the formation of isostructural compounds with very different magnetic behaviors due to the compensation or not of the different spins involved in each lattice. Below TN, the magnetic order in these compounds varies from ferrimagnetic behavior for 1 and 2 to an antiferromagnetic behavior with a weak spin canting for 3. Structure refinements of 2 and 3 at low temperature (45 K) have been carried out combining synchrotron X-ray and high-resolution neutron diffraction in a multipattern approach. The magnetic structures have been determined from the difference patterns between the neutron data in the paramagnetic and the magnetically ordered regions. These difference patterns have been analyzed using a simulated annealing protocol and symmetry analysis techniques. The obtained magnetic structures have been further rationalized by means of ab initio DFT calculations. The direction of the magnetic moment of each compound has been determined. The easy axis of the MIIfor compound 1 (FeII) is along the c axis; for compound 2 (CoII), the moments are mainly within the ab plane; finally, for compound 3 (MnII), the calculations show that the moments have components both in the ab plane and along the c axis.
authors.affiliation: Institut Laue-Langevin , 71 Avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, France.
authors.forename: Lidia
authors.initials: L
authors.lastname: Mazzuca
authors.affiliation: Centro Universitario de la Defensa de Zaragoza , Ctra Huesca s/n, Zaragoza 50090, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Cañadillas-Delgado
authors.affiliation: Institut Laue-Langevin , 71 Avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, France.|Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza , C/Pedro Cerbuna 12, E-50009 Zaragoza, Spain.
authors.forename: J Alberto
authors.initials: JA
authors.lastname: Rodríguez-Velamazán
authors.affiliation: Institut Laue-Langevin , 71 Avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, France.
authors.forename: Oscar
authors.identifier: http://orcid.org/0000-0001-6452-8830
authors.initials: O
authors.lastname: Fabelo
authors.affiliation: Consiglio Nazionale delle Ricerche, Istituto CNR-SPIN , Sede Temporanea di Chieti, 66100 Chieti, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Scarrozza
authors.affiliation: Consiglio Nazionale delle Ricerche, Istituto CNR-SPIN , UOS L'Aquila, 67100 L'Aquila, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Stroppa
authors.affiliation: Consiglio Nazionale delle Ricerche, Istituto CNR-SPIN , Sede Temporanea di Chieti, 66100 Chieti, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Picozzi
authors.affiliation: Department of Chemistry and TKL of Metal and Molecule-Based Material Chemistry, Nankai University , Tianjin 300071, China.
authors.forename: Jiong-Peng
authors.initials: JP
authors.lastname: Zhao
authors.affiliation: Department of Chemistry and TKL of Metal and Molecule-Based Material Chemistry, Nankai University , Tianjin 300071, China.
authors.forename: Xian-He
authors.initials: XH
authors.lastname: Bu
authors.affiliation: Institut Laue-Langevin , 71 Avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, France.
authors.forename: Juan
authors.initials: J
authors.lastname: Rodríguez-Carvajal