Transverse magneto-optical Kerr effect measured using phase modulation

An ellipsometric configuration for measurement of complex transverse magneto-optical Kerr effect is described that uses photoelastic modulator (PEM). The real and imaginary parts of the complex transverse Kerr effect are represented as small perturbations of ellipsometric angles $\psi$ and $\Delta$. The measurement based on null ellipsometry and zone averaging gives high signal typical for modulation techniques and insensitivity to other magnetisation components and system imperfections. The method is demonstrated by the measurement of transverse component during magnetisation reversal in thin cobalt film.