We investigated the optical absorption spectra of the time-reversal-odd antiferromagnet ${\mathrm{ErCrO}}_3$ under an applied electric field ($\mathbf{E}$). This material, with its two distinct magnetic sites (${\mathrm{Er}}^{3+}$ and ${\mathrm{Cr}}^{3+}$), exhibits successive antiferromagnetic (AFM) transitions at $T_{\mathrm{N}}\approx 133\mathrm{K}$ and $T_{\text{SR}}\approx 10\mathrm{K}$. We observed nonreciprocal directional dichroism induced by $\mathbf{E}$ (ENDD) in the AFM phases, spanning the near-infrared to visible light regions. The phenomenon is explained by the electrotoroidic effect, where a magnetic toroidal moment is induced by the applied electric field. We also found that the spatial distributions of ENDD—reflecting magnetic domain structures—obtained at photon energies corresponding to ${\mathrm{Er}}^{3+}f\text{−}f$ and ${\mathrm{Cr}}^{3+}d\text{−}d$ transitions, were in good agreement. The result indicates a strong interplay between ${\mathrm{Er}}^{3+}4f$ and ${\mathrm{Cr}}^{3+}3d$ moments in the AFM phases of this rare-earth orthochromite. The combination of ENDD spectroscopy and microscopy is a powerful tool for elucidating site-specific magnetic information in time-reversal-odd antiferromagnets such as altermagnets.

Close

PrevNext

View figure in article

• Domains
• Magneto-optics
• Antiferromagnets
• Optical microscopy