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A. Zorko

Publications and source records attributed to A. Zorko.

60 records · Page 4Linked to original sources
arXiv2009

Spin amplitude modulation driven magnetoelectic coupling in the new multiferroic FeTe$_2$O$_5$Br

Magnetic and ferroelectric properties of layered geometrically frustrated cluster compound FeTe$_2$O$_5$Br were investigated with single-crystal neutron diffraction and dielectric measurements. Incommensurate amplitude modulated magnetic order with the wave vector $\bf{q}$=($\half$, 0.463, 0) develops below $T_N=10.6(2) {\rm K}$. Simultaneously, a ferroelectric order with the spontaneous polarization perpendicular to ${\bf q}$ and to Fe$^{3+}$ magnetic moments emerges. The observed ferroelectricity and extraordinary linear scaling of the ferroelectric and magnetic order parameter are provoked by the striction of the intercluster Fe-O-Te-O-Fe bridges leading to the shift of Te$^{4+}$ ions and polarization of their lone-pair electrons.

cond-mat.mtrl-sci↗
arXiv2008

Dzyaloshinsky-Moriya Anisotropy in the Spin-1/2 Kagomé Compound ZnCu$_{3}$(OH)$_{6}$Cl$_{2}$

We report the determination of the Dzyaloshinsky-Moriya interaction, the dominant magnetic anisotropy term in the \kagome spin-1/2 compound {\herbert}. Based on the analysis of the high-temperature electron spin resonance (ESR) spectra, we find its main component $|D_z|=15(1)$ K to be perpendicular to the \kagome planes. Through the temperature dependent ESR line-width we observe a building up of nearest-neighbor spin-spin correlations below $\sim$150 K.

cond-mat.str-el↗
arXiv2008

Easy-Axis Kagomé Antiferromagnet: Local-Probe Study of Nd$_3$Ga$_5$SiO$_{14}$

We report a local-probe investigation of the magnetically anisotropic kagomé compound Nd$_3$Ga$_5$SiO$_{14}$. Our zero-field $μ$SR results provide a direct evidence of a fluctuating collective paramagnetic state down to 60 mK, supported by a wipe-out of the Ga nuclear magnetic resonance (NMR) signal below 25 K. At 60 mK a dynamics crossover to a much more static state is observed by $μ$SR in magnetic fields above 0.5 T. Accordingly, the NMR signal is recovered at low $T$ above a threshold field, revealing a rapid temperature and field variation of the magnetic fluctuations.

cond-mat.str-el↗
arXiv2007

Recovering Metallicity in A4C60: The Case of Monomeric Li4C60

The restoration of metallicity in the high-temperature, cubic phase of Li4C60 represents a remarkable feature for a member of the A4C60 family (A = alkali metal), invariably found to be insulators. Structural and resonance technique investigations on Li4C60 at T > 600 K, show that its fcc structure is associated with a complete (4e) charge transfer to C60 and a sparsely populated Fermi level. These findings not only emphasize the crucial role played by lattice symmetry in fulleride transport properties, but also re-dimension the role of Jahn-Teller effects in band structure determination. Moreover, they suggest the present system as a potential precursor to a new class of superconducting fullerides.

cond-mat.str-el↗
arXiv2003

Magnetic Anisotropy of SrCu$_2$(BO$_3$)$_2$ System as Revealed by X-Band ESR

X-band ESR measurements on a single crystal of the highly frustrated SrCu$_2$(BO$_3$)$_2$ system are shown to provide an essential inspection of the magnetic anisotropy present in this compound. The very broad absorption lines seem to be consistent with the largest anisotropy term, namely, the antisymmetric Dzyaloshinsky-Moriya (DM) interaction allowed by symmetry. However, the previously well-accepted model of only interdimer interaction is generalized with additional intradimer DM terms. Moreover, spin-phonon coupling is recognized as the cause on the linewidth broadening with increasing temperature.

cond-mat.str-el↗