Enhanced Magnetic Hardness in a Nanoscale Metal–Organic Hybrid Ferrimagnet

Abstract

A new layered metal-organic hybrid compound, namely, [Co(3)(μ(3 -OH)(2)(BTP)(2)] (1; BTP=4-(3-bromothienyl)phosphonate), is reported. The inorganic layer can be viewed as a pseudo-Kagomé lattice composed of corner-sharing irregular triangles of Co(3) (μ(3)-OH), with the cavities filled with the PO(3) groups. The interlayer space is occupied by the 3-bromothienyl groups of BTP(2-). The bulk sample of compound 1 experiences a long-range ferromagnetic ordering below 30.5 K, with a coercivity (H(c)) of 5.04 kOe at 5 K. A systematic study on the size-dependent magnetic coercivity of 1 reveals that the coercivity of 1 increases with reduced particle size from the micrometer to the nanometer scale. When the particle size is about 50-200 nm, the coercivity reaches 24.2 kOe at 5 K. The results demonstrate that compound 1 can vary from a soft magnet to one of the hardest molecule-based magnets, simply by reducing the particle size to nanoscale region.

Dynamic Motion of Organic Ligands in Polar Layered Cobalt Phosphonates

“…The cobalt compounds are magnetically attractive due to the presence of strong spin–orbit coupling of the Co II ion . A number of cobalt phosphonates have been reported to show an interesting magnetic behavior, such as ferrimagnetism, weak ferromagnetism, and metamagnetism . Polar cobalt compounds can offer unique opportunities for exploring new multifunctional materials, such as multiferroic materials combining polarity and magnetism .…”

“…[46] A number of cobalt phosphonates have been reported to show an interesting magnetic behavior,s uch as ferrimagnetism, weak ferromagnetism, and metamagnetism. [47,48] Polar cobalt compounds can offer unique opportunities for exploring new multifunctional materials, such as multiferroic materials combining polarity and magnetism. [49][50][51] Bearing this in mind, we also studied the magnetic properties of compounds 1-4.F igures 4a nd S17 in the Supporting Information show the temperature-dependentm agnetic susceptibilities measured under ad irect current (dc) field of 1kOe and at emperature range of 1.9-300 K. At room temperature,t he c m T products for compounds 1-4 are 3.08, 3.20, 3.38, and 3.31 cm 3 mol À1 K, respectively.T hese values are much larger than the spin-only value of 1.88 cm 3 mol À1 Kf or isolated Co II ions (S = 3/2 and g = 2.0), attributed to the orbital contributiono ft he octahedral cobalt(II) ion.…”

Solvent induced rapid modulation of micro/nano structures of metal carboxylates coordination polymers: mechanism and morphology dependent magnetism

“…However, there was very few reports discussed the magnetic properties of CPs micro/nanostructures54. Herein, the magnetic measurements were carried out and analyzed for Co-pydc CPs.…”

Homochiral Cobalt Phosphonates Containing Δ‐Type Chains with a Tunable Interlayer Distance and a Field‐Induced Phase Transition

“…In recent years, we have focused on metal phosphonates with interesting magnetic, [11] optical, [12] and proton conductivity [13] properties. A number of cobalt phosphonates have been assembled that display metamagnetism, [14] weak ferromagnetism, [15] ferrimagnetism, [16] and tunable magnetic behaviors. [17] By using 4-(3-bromothienyl)phosphonate (BTP), a layered Co II compound [Co 3 (m 3 -OH) 2…”

“…A number of cobalt phosphonates have been assembled that display metamagnetism,14 weak ferromagnetism,15 ferrimagnetism,16 and tunable magnetic behaviors 17. By using 4‐(3‐bromothienyl)phosphonate (BTP), a layered Co II compound [Co 3 (μ 3 ‐OH) 2 (BTP) 2 ]16b with a pseudo‐Kagomé frustrated lattice was obtained showing long‐range ferromagnetic ordering. As a continuous effort towards the construction of frustrated antiferromagnets with multiple functions, herein we report the first examples of homochiral metal phosphonates based on ( S )‐ or ( R )‐[(1‐cyclohexylethyl)amino]methylphosphonic acid (cyampH 2 ; Scheme ), namely, [Co 2 (μ 3 ‐OH)( S ‐cyamp)(CH 3 COO)] ( S ‐ 1 ), [Co 2 (μ 3 ‐OH)( R ‐cyamp)(CH 3 COO)] ( R ‐ 1 ), [Co 2 (μ 3 ‐OH)(S‐cyamp)(C 7 H 15 COO)] ( S ‐ 2 ), and [Co 2 (μ 3 ‐OH)( R ‐cyamp)(C 7 H 15 COO)] ( R ‐ 2 ).…”