Tm(iii) complexes undergoing slow relaxation of magnetization: exchange coupling and aging effects.
The present study focuses on the dynamic magnetic behaviour of exchange coupled 3d-4f complexes containing the scarcely investigated non-Kramers Tm3+center, the 3d metal ions being either the low-spin Fe3+(1) or the diamagnetic Co3+(2) ion. Both complexes display field-induced slow relaxation of magnetization. The field and temperature dependences of the relaxation rate provided indication of relevant contributions from quantum tunnelling, direct, Orbach and Raman processes, with only minor effects from exchange coupling interactions. Furthermore, the aged sample of 2 exhibited an additional relaxation process, possibly due to structural modifications accompanied by solvent loss, highlighting the importance of a careful consideration of this factor when analysing the magnetization dynamics in solvated systems.
INSTM Research unit & Dipartimento di Chimica "U. Schiff", Università degli Studi di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino, Fl, Italy. lorenzo.sorace@unifi.it.
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http://orcid.org/0000-0002-2515-0465
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Amjad
Departament de Química Inorgànica i Orgànica, Secció de Química Inorgànica, i Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, Martí i Franquès 1-11, E-08028 Barcelona, Spain.
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Figuerola
INSTM Research unit & Dipartimento di Chimica "U. Schiff", Università degli Studi di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino, Fl, Italy. lorenzo.sorace@unifi.it.
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http://orcid.org/0000-0003-4785-1331
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Sorace