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S e p t e m b e r 2 4 - 2 6 , 2 0 1 8 | B u d a p e s t , H u n g a r y
OF EXCELLENCE
IN INTERNATIONAL
MEETINGS
YEARS
Magnetic Materials 2018 Materials Science and Nanotechnology | Volume 2
MAGNETISM AND
MAGNETIC MATERIALS
2nd International Conference on
Cyril Rajnák, Mater Sci Nanotechnol 2018, Volume 2
FIELD SUPPORTED SLOW MAGNETIC
RELAXATION IN HEXACOORDINATE
CO(II) COMPLEXES WITH EASY PLANE
ANISOTROPY
Cyril Rajnák
University of Ss. Cyril and Methodius, Macedonia
Single molecule magnets known up to date cover several classes of
transition metal complexes: there are polynuclear and mononuclear, 3d
and 4f, heteronuclear 3d-4f, field induced, and field suppressed, with single
mode and multimode relaxation channel systems. Over the past years an
increased interest is paid to mononuclear 3d complexes mainly for their easy
synthesis, stability, and low price. They involve high-spin Cr (III), Mn (III), Fe
(III), Fe (II), Fe (I), Co (II), Ni (I), and Ni (II) complexes. Also, the key factor
– the magnetic anisotropy is much easily tuned by a rational synthesis for
mononuclear complexes. Considerable attention has been paid to the class
of mononuclear Co (II) complexes, mostly tetracoordinate, pentacoordinate,
and hexacoordinate. These complexes possess a large magnetic anisotropy
expressed by the axial zero-field-splitting (ZFS) parameter D. However,
the language in terms of the D- and E-parameters implies that the spin
Hamiltonian formalism is legitimate to apply which holds true only for the
non-degenerate ground electronic terms of the A- or B-symmetry (point-
group irreducible representation); this is the case of quasitetrahedral Co (II)
complexes. For pentacoordinate and hexacoordinate complexes one should
be careful since here also the degenerate ground electronic terms occur: 4E
for the geometry of tetragonal pyramid (the coordination number cn=4+1)
and 4Eg for the elongated tetragonal bipyramid (cn=4+2). Application of
the spin Hamiltonian (SH) formalism to magnetic data fitting and/or ab
initio calculations for systems with degenerate ground term is conceptually
mistaken since SH approach utilizes the non-degenerate perturbation theory.
Recent Publications
1. Schäfer B, Rajnák C, Šalitroš I, Fuhr O, Klar D, Schmitz-Antoniak C,
Weschke E, Wende H, Ruben M (2013). Room temperature switching
Cyril Rajnák has obtained an MSc and then a RNDr
from the University of Ss. Cyril and Methodius in 2009
and 2010, respectively. He received his PhD from the
University of Strasbourg in 2014 under the guidance
of Prof. Mario Ruben. He received second PhD from
the University of Ss. Cyril and Methodius under the su-
pervision of Prof. Roman Boča. In 2015, he joined the
Alma Mater as an Assistant Professor. His research is
focused on organic and inorganic synthesis and de-
velopment of single-molecule (Ion) magnets. He has
published more than 20 reputed journals.
BIOGRAPHY
of a neutral molecular iron(ii) complex.
Chemical Communications. 49:10986-
10988.
2. Rajnák C, Titiš J, Fuhr O, Ruben M, Boča
R (2014) Single-molecule magnetism
in a pentacoordinate cobalt(II) complex
supported by an antenna ligand.
Inorganic Chemistry. 53:8200-8202.
3. Lomjanský D, Moncol’ J, Rajnák C,
Titiš J, Boča R (2017) Field effects
to slow magnetic relaxation in a
mononuclear Ni(II) complex. Chemical
Communications. 53: 6930-6932.
4. Boca R, Rajnak C, Titis J, Valigura D,
(2017) Field supported slow magnetic
relaxation in a mononuclear Cu(II)
complex. Inorganic Chemistry.
56:1478−1482.
5. Rajnák C, Varga F, Titiš J, Moncoľ J,
Boča R (2017) Field-Supported Single-
Molecule Magnets of Type [Co(bzimpy)
X2]. European Journal of Inorganic
Chemistry 2017:1915–1922.