Scopul nostru este sprijinirea şi promovarea cercetării ştiinţifice şi facilitarea comunicării între cercetătorii români din întreaga lume.
Autori: Mihai A. Girtu, Charles M. Wynn, Jie Zhang, Joel S. Miller, and Arthur J. Epstein
Editorial: Phys. Rev. B, 61, p.429, 2000.
We report magnetic studies of Fe(TCNE)2x(CH2Cl2), a member of the family of high Tc molecule-based magnets, M(TCNE)2 y(solvent) (M = V, Mn, TCNE = tetracyanoethelyne). Based on extensive static and dynamic magnetic measurements we show that this system has a complex magnetic behavior, with a mixture of ferrimagnetic and random anisotropy characteristics. The constricted hysteresis curve with a spin-flop shape, the ac susceptibility in the presence of a dc field, consistent with the spin-flop picture, and the remanent magnetization suggest ferrimagnetic behavior. The ac susceptibility data in zero dc field have modest frequency dependence suggesting glassiness, while the FC/ZFC magnetization data show irreversibilities, starting at ~97 K, and increasing below ~ 20 K, all consistent with the behavior of reentrant random anisotropy magnets (RAM). Ferromagnetic-like scaling analyses provide a critical temperature Tc = 97 K and the critical exponents beta = 0.45 and delta = 2.5, relatively consistent with random anisotropy magnet predictions. Also, the curvature of the T
Cuvinte cheie: molecular magnets