Magnetic Dimensionality of Metal Formate M[(H2O)(2)(HCOO)(2)] Compounds (M = Co(II), Cu(II))

resumo

The magnetic properties of two metal formate systems with formula M[(H2O)(2)(HCOO)(2)], which are isostructural, are described (M = Co, Cu). These compounds contain two different crystallographic metal centers (M2+), in octahedral coordination, which are connected through (HCOO) bridges, leading to the formation of two types of infinite chains: M(1) - HCOO - M(2) and M(1) - HCOO - M(1). The packing of these chains, along with hydrogen bonds, generates a 3-D framework. Cu-sample presents an usual paramagnetic behavior, following Curie law. On the contrary, Co-sample has an order-disorder magnetic transition, further analyzed by means of magnetization and specific heat. These data lead us to conclude an anisotropic environment for Co ions, as expected for an octahedral neighborhood. Critical exponents of these thermodynamic quantities around the thermal transition are in accordance with 3-D model. This is a very important remark, since a previous work had shown that the magnetic phase transition is 2-D.

palavras-chave

HEAT-CAPACITY; CRYSTAL-STRUCTURE; DIHYDRATE; TRANSITION

categoria

Engineering; Physics

autores

Sousa, LLL; Barbosa, GF; Machado, FLA; Araujo, LRS; Brandao, P; Reis, MS; Rocco, DL

nossos autores

agradecimentos

This work was supported in part by PROPPI - UFF, CNPq, CAPES, FINEP, FACEPE and FAPERJ (Brazilian Agencies).

Partilhe este projeto

Publicações similares

Usamos cookies para atividades de marketing e para lhe oferecer uma melhor experiência de navegação. Ao clicar em “Aceitar Cookies” você concorda com nossa política de cookies. Leia sobre como usamos cookies clicando em "Política de Privacidade e Cookies".