39 research outputs found
Magnetic systems at criticality: different signatures of scaling
Different aspects of critical behaviour of magnetic materials are presented
and discussed. The scaling ideas are shown to arise in the context of purely
magnetic properties as well as in that of thermal properties as demonstrated by
magnetocaloric effect or combined scaling of excess entropy and order
parameter. Two non-standard approaches to scaling phenomena are described. The
presented concepts are exemplified by experimental data gathered on four
representatives of molecular magnets.Comment: 33 pages, 16 figure
Magnetization dynamics and coherent spin manipulation of a propeller Gd(III) complex with the smallest helicene ligand
A homoleptic gadolinium(III) complex with the smallest helicene-type ligand, 1,10-phenanthroline-N,N'-dioxide (phendo) [Gd(phendo)(4)](NO3)(3)center dot xMeOH (phendo = 1,10-phenanthroline-N,N'-dioxide, MeOH = methanol), shows slow relaxation of the magnetization characteristic for Single Ion Magnets (SIM), despite negligible magnetic anisotropy, confirmed by ab initio calculations. Solid state dilution magnetic and EPR studies reveal that the magnetization dynamics of the [Gd(phendo)(4)](3+) cation is controlled mainly by a Raman process. Pulsed EPR experiments demonstrate long phase memory times (up to 2.7 mu s at 5 K), enabling the detection of Rabi oscillations at 20 K, which confirms coherent control of its spin state.</p
Enforcing Multifunctionality: A Pressure-Induced Spin-Crossover Photomagnet
Photomagnetic compounds are usually
achieved by assembling preorganized
individual molecules into rationally designed molecular architectures
via the bottom-up approach. Here we show that a magnetic response
to light can also be enforced in a nonphotomagnetic compound by applying
mechanical stress. The nonphotomagnetic cyano-bridged Fe<sup>II</sup>鈥揘b<sup>IV</sup> coordination polymer {[Fe<sup>II</sup>(pyrazole)<sub>4</sub>]<sub>2</sub>[Nb<sup>IV</sup>(CN)<sub>8</sub>]路4H<sub>2</sub>O}<sub><i>n</i></sub> (<b>FeNb</b>) has been
subjected to high-pressure structural, magnetic and photomagnetic
studies at low temperature, which revealed a wide spectrum of pressure-related
functionalities including the light-induced magnetization. The multifunctionality
of <b>FeNb</b> is compared with a simple structural and magnetic
pressure response of its analog {[Mn<sup>II</sup>(pyrazole)<sub>4</sub>]<sub>2</sub>[Nb<sup>IV</sup>(CN)<sub>8</sub>]路4H<sub>2</sub>O}<sub><i>n</i></sub> (<b>MnNb</b>). The <b>FeNb</b> coordination polymer is the first pressure-induced spin-crossover
photomagnet