Naslov
Magnetic anisotropy of spin tetramer system SeCuO3 studied by torque magnetometry and ESR spectroscopy

Autori
Herak, Mirta ; Žilić, Dijana ; Grubišić Čabo, Antonija ; Rakvin, Boris ; Salamon, Krešimir ; Milat, Ognjen ; Berger, Helmuth

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Dynamics in Soft Matter Probed by Advanced EPR Techniques / Žilić, Dijana ; Ilakovac Kveder, Marina - Zagreb : Institut Ruđer Bošković, 2014, 9-9

ISBN
978-953-6690-99-2

Skup
Dynamics in Soft Matter Probed by Advanced EPR Techniques

Mjesto i datum
Lužnica, Hrvatska, 05.05.2014. - 09.05.2014

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
elektronska paramagnetska rezonancija; meka tvar
(electron paramagnetic resonance; soft matter)

Sažetak
Low – dimensional spin systems present a fertile ground for study of magnetism. Their relatively simple magnetic lattices are ideal for analytical and numerical theoretical investigations. At the same time such systems can be found in real materials thus enabling a comparison of experimental study with theory. Of special interest are spin S = 1/2 systems in which the interactions of spins are usually well described by isotropic Heisenberg Hamiltonian and the magnetic anisotropy mostly comes from the g factor anisotropy. Presence of small anisotropic exchange interaction can have a profound influence on the ground state and low-energy excitations of these systems. We present an experimental study of macroscopic and microscopic magnetic anisotropy of a novel low-dimensional spin S=1/2 system SeCuO3 using uncommon experimental approach of combining torque magnetometry and ESR spectroscopy.1 It was proposed recently that magnetic lattice of SeCuO3 consists of isolated spin tetramers2 (Fig.1). However, theoretical model3 failed to describe the measured magnetic susceptibility, and strong temperature dependence of g factor and rotation of macroscopic magnetic axes were also reported.2 We performed detailed measurements of the temperature dependence of ESR spectra which enabled us to compare the rotation of the g tensor with the rotation of macroscopic magnetic axes obtained from torque. Rotation of g tensor can account for rotation of magnetic axes only below below T= 50K (Fig. 2). Temperature dependence of magnetic susceptibility anisotropy we obtain from torque points out importance of including anisotropic exchange interaction in the spin Hamiltonian of SeCuO3, which is corroborated by our ESR linewidth analysis. Our results show that existing theory is insufficient to explain the effects observed in this system and call for further theoretical and experimental investigations of low-dimensional spin systems.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kemija

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