Angular dependence of exchange bias and magnetization reversal controlled by electric-field-induced competing anisotropies.

Combination of exchange-biased systems and FE materials$^{\mathrm{\thinspace }}$gives a new avenue to study angular dependence of exchange bias and achieve reversible electric-field-controlled magnetization reversal. We study the angular dependence of electric-field-controlled exchange bias and magnetization reversal in CoFeB/IrMn/Pb(Mg$_{\mathrm{1/3}}$Nb$_{\mathrm{2/3}})_{\mathrm{0.7}}$Ti$_{\mathrm{0.3}}$O$_{\mathrm{3}}$. It is demonstrated that the ratio of the exchange-coupled unidirectional anisotropy and the uniaxial anisotropy of the FM layer, as well as their relative orientation can be dramatically and continuously tuned via electric fields. Simulations confirm that the electric-field-controlled exchange bias originates from the competition between the uniaxial anisotropy induced by the piezostrain and the exchange-coupled unidirectional anisotropy. Moreover, electric-field-controlled magnetization reversal was realized at zero magnetic field.