Dresden 2014 – wissenschaftliches Programm

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KR: Fachgruppe Kristallographie

KR 5: Multiferroics II (MA jointly with DF, DS, KR, TT)

KR 5.9: Vortrag

Mittwoch, 2. April 2014, 11:45–12:00, HSZ 04

The multiferroic CuCrO₂ compound: interlayer exchange and domain population — •Matthias Frontzek — Laboratory for Neutron Scattering, Paul Scherrer Institut, 5232 Villigen-PSI, Switzerland

Multiferroic materials have become of interest for their unusual low-temperature properties in general, and the tunability of the magnetic structure through an electric field and the electric polarization through a magnetic field in particular. The most promising candidates for such controllable multiferroics have been found among the materials with inherent geometric magnetic frustration.

Among these, the delafossite CuCrO₂, which crystallizes in the rhombohedral R3m space group, is a multiferroic compound with an apparent strong coupling of spin and charge. In contrast to other multiferroic compounds CuCrO₂ shows a spontaneous electric polarization upon antiferromagnetic ordering without an accompanying structural phase transition, thus the magnetic ordering alone breaks the inversion symmetry. The peculiar magnetic structure of CuCrO₂ allows the direct quantitative analysis of the domain population.

In our contribution, we present a detailed study on CuCrO₂ single crystals using neutron diffraction in applied electric and magnetic fields. With the fields we were able to tune the multiferroic states in CuCrO₂ and could directly relate them to the underlying domain physics. Our results allow the re-interpretation of macroscopic measurements and show that the p−d hybridization is the dominant spin-charge coupling mechanism.