Two-magnon absorption in Nd₂CuO₄ caused by the linear magnetoelectric effect of exchange nature

Abstract

The two-magnon absorption of light in Nd₂CuO₄ caused by magnetodipole and electrodipole exchange mechanism has been analyzed. It is shown that in the range of small frequencies (of the order of spin-wave activation energies) the magnetodipole and electrodipole mechanism lead to different absorption coefficient dependence upon the frequency. In contrast with the case of collinear antiferromagnets the intensity of two-magnon absorption due to exchange mode is of the same order as that of the absorption intensity due to acoustic mode.

Key Words:

• Magnetoelectric effect
• two-magnon absorption
• spin wave.