The Electric-Field Controllable Non-Volatile 35$^{\circ}$ Rotation of Magnetic Easy Axis in Magnetoelectric CoFeB/(001)-Cut Pb(Mg$_{1/3}$Nb$_{2/3}$)O$_{3}$-25%PbTiO$_{3}$ Heterostructure

Using in situ electric-field-modulated anisotropic magnetoresistance measurement, a large reversible and nonvolatile in-plane rotation of magnetic easy axis of ~35° between the positive and negative electrical poling states is demonstrated in Co40Fe40B20/(001)-cut Pb(Mg1/3Nb2/3)O3-0.25PbTiO3 (PMN-PT). The specific magnetoelectric coupling mechanism therein is experimentally verified to be related to the synchronous in-plane strain rotation induced by 109° ferroelastic domain switching in the (001)-cut PMN-PT substrate.