Switching of antiferromagnetic states in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mi>LiCoPO</mml:mi></mml:mrow><mml:mn>4</mml:mn></mml:msub></mml:math> as investigated via the magnetoelectric effect
Vilmos Kocsis, Y. Tokunaga, Yoshinori Tokura, Y. Taguchi
Abstract
The linear magnetoelectric (ME) effect allows for the selection or switching between two antiferromagnetic (AFM) states via the application of large electric $(E)$ and magnetic $(H)$ fields. Once an AFM state is selected, it is preserved by an energy barrier, even when the fields are removed. Using a simple phenomenological model, we find that this energy barrier, which is needed to switch the AFM state, is proportional to the product of the $E$ and $H$ coercive fields ${(EH)}_{\mathrm{C}}$. We measured the field and temperature dependence of ${(EH)}_{\mathrm{C}}$ in ${\mathrm{LiCoPO}}_{4}$ for two different field configurations, and the data show the temperature variation of ${(EH)}_{\mathrm{C}}\ensuremath{\sim}{({T}_{\mathrm{N}}\ensuremath{-}T)}^{3/2}$ in good agreement with the model. We also investigated the dynamics of the AFM domain switching using pulsed $E$-field measurements. It was found that the coercive field ${(EH)}_{\mathrm{C}}$ follows a power-law frequency dependence and is well described in the framework of the Ishibashi-Orihara model, implying one-dimensional character of domain wall propagation.