title: Magnetic properties of manganese based one-dimensional spin chains.
abstract: We have correlated the structure-property relationship of three manganese-based inorganic-organic hybrid structures. Compound 1, [Mn2(OH-BDC)2(DMF)3] (where BDC = 1,4-benzene dicarboxylic acid and DMF = N,N'-dimethylformamide), contains Mn2O11 dimers as secondary building units (SBUs), which are connected by carboxylate anions forming Mn-O-C-O-Mn chains. Compound 2, [Mn2(BDC)2(DMF)2], contains Mn4O20 clusters as SBUs, which also form Mn-O-C-O-Mn chains. In compound 3, [Mn3(BDC)3(DEF)2] (where DEF = N,N'-diethylformamide), the distorted MnO6 octahedra are linked to form a one-dimensional chain with Mn-O-Mn connectivity. The magnetic properties were investigated by means of magnetization and heat capacity measurements. The temperature dependent magnetic susceptibility of all the three compounds could be nicely fitted using a one-dimensional S = 5/2 Heisenberg antiferromagnetic chain model and the value of intra-chain exchange coupling (J/k(B)) between Mn(2+) ions was estimated to be ∼1.1 K, ∼0.7 K, and ∼0.46 K for compounds 1, 2, and 3, respectively. Compound 1 does not undergo any magnetic long-range-order down to 2 K while compounds 2 and 3 undergo long-range magnetic order at T(N) ≈ 4.2 K and ≈4.3 K, respectively, which are of spin-glass type. From the values of J/k(B) and T(N) the inter-chain coupling (J(⊥)/k(B)) was calculated to be about 0.1J/k(B) for both compounds 2 and 3, respectively.
authors.affiliation: School of Chemistry, Indian Institute Science Education and Research, Thiruvananthapuram, India. sukhendu@iisertvm.ac.in.
authors.forename: K S
authors.initials: KS
authors.lastname: Asha
authors.affiliation: School of Physics, Indian Institute of Science Education and Research, Thiruvananthapuram, India. rnath@iisertvm.a.cin.
authors.forename: K M
authors.initials: KM
authors.lastname: Ranjith
authors.affiliation: School of Physics, Indian Institute of Science Education and Research, Thiruvananthapuram, India. rnath@iisertvm.a.cin.
authors.forename: Arvind
authors.initials: A
authors.lastname: Yogi
authors.affiliation: School of Physics, Indian Institute of Science Education and Research, Thiruvananthapuram, India. rnath@iisertvm.a.cin.
authors.forename: R
authors.initials: R
authors.lastname: Nath
authors.affiliation: School of Chemistry, Indian Institute Science Education and Research, Thiruvananthapuram, India. sukhendu@iisertvm.ac.in.
authors.forename: Sukhendu
authors.initials: S
authors.lastname: Mandal