Neutron Diffraction Studies of the Molecular Compound [Co2(bta)]n (H4bta =1,2,4,5-Benzenetetracarboxylic Acid): In the Quest of Canted Ferromagnetism

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• 作者：Oscar Fabelo ; Laura Ca帽adillas-Delgado ; Jorge Pas谩n ; Pau D铆az-Gallifa ; Catalina Ruiz-P茅rez ; Francesc Lloret ; Miguel Julve ; In茅s Puente Orench ; Javier Campo ; Juan Rodr铆guez-Carvajal
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：November 4, 2013
• 年：2013
• 卷：52
• 期：21
• 页码：12818-12827
• 全文大小：588K
• 年卷期：v.52,no.21(November 4, 2013)
• ISSN：1520-510X

文摘

The exchange mechanism and magnetic structure of the organic鈥搃norganic layered molecule-based magnet [Co₂(bta)]_n (1) (H₄bta =1,2,4,5-benzenetetracarboxylic acid) have been investigated through variable-temperature magnetic susceptibility measurements and supported with a series of neutron diffraction experiments. Cryomagnetic studies have shown an antiferromagnetic ordering at a transition temperature of 16 K that is followed by the appearance of a weak ferromagnetism below 11 K. The weak antiferromagnetic interlayer interaction plays an important role in this system in spite of the long interlayer separation. A ferromagnetic ordering is induced by applied magnetic fields greater than 1800 G (metamagnetic behavior), and a slow magnetic relaxation from this ferromagnetic phase to the antiferromagnetic one is observed. The magnetic structure of 1 has been elucidated at low temperatures in zero field by neutron powder diffraction measurements and was found to be of antiferromagnetic nature with the local cobalt(II) spins (magnetic moments) being aligned ferromagnetically in the ac plane and antiferromagnetically coupled along the crystallographic b axis. No evidence for a long-range spontaneous ferromagnetic component below 11 K was observed in the neutron experiment.