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MA: Fachverband Magnetismus
MA 7: Poster Magnetism I
MA 7.28: Poster
Montag, 9. März 2026, 09:30–12:30, P2
Investigating magnetoelastic effects in multiferroic CoCr2O4 — •Abdelrahman Elsaid1, Ryan Morrow1, Robert Kluge1, Sabine Wurmehl1, Bernd Büchner1,2, and Vilmos Kocsis1 — 1IFW-Dresden — 2TU-Dresden
In a previous study based on optical spectroscopy, chromium-based spinels were found to exhibit significant magnetoelasticity if the magnetic A-site ion was occupied by a Jahn-Teller active ion. While the sentiment of this finding is true, optical spectroscopy is mostly sensitive to symmetry lowerings, and magnetoelasticity - meaning any sort of lattice deformation - may remain unnoticed in optics. Moreover, one of the chromium spinels with orbital singlet ions, CoCr2O4 is a known multiferroic, where the magnetoelectric interactions are originating from the conical spin order. It is an interesting question whether the polar distortion accompanying the spin order has a noticeable effect on the size of the unit cell, namely: can a piezo-magnetoelectric effect appear in CoCr2O4?
This motivated us to investigate CoCr2O4 using high-sensitivity capacitance dilatometry, a method not just sensitive to symmetry lowerings, but also to delicate changes in the size of the unit cell. We have found that, in line with the optical spectroscopy measurements, the unit cell shows zero change in size upon the appearance of the magnetic order. However, the application of magnetic field still reveals a significant magnetostriction in the magnetoelectric conical phase, which suggests the presence of piezo-magnetoelectric interactions.
Keywords: Piezomagnetism; Multiferroic; Magnetolectricity; Swedenborgites; Spin orbit coupling