A study is made of the surface corrugation during thermal cycling of ferromagnetic shape memory alloys (FSMA). This specific feature is a property of FSMA alloys and is a consequence of martensitic phase transformations not necessarily connected with surface defects of the material. The surface relief structure was studied together with martensite and magnetic domain structure changes during thermal cycling of the samples with the aid of differential polarized light microscopy. The analysis was facilitated making use of auxiliary reference grids applied to the surface of the samples.

The martensitic and magnetic domain structures of polycrystalline and single-crystal samples of ferromagnetic Heusler alloys of the Ni-Mn-Ga and Co-Ni-Ga families have been revealed and studied using optical microscopy. The main mechanisms of formation and interaction of 90° and 180° magnetic domains have been described.

A method of localized polarization-optical measurement of dielectric hysteresis loop parameters on microscopical areas of ferroelectric samples combined with simultaneous observation of their domain structure is proposed. A sensitive two-beam differential polarization-optical hysteresisgraph is built for performing the experiments. Examples are given of the study of slow domain structure relaxation processes and dielectric hysteresis curves of lead germanate Pb 5 Ge 3 O 11 .

Direct observations of the austenite and martensite twin and magnetic domain structures are combined with thermomagnetic analysis (low-field AC susceptibility temperature measurements) of phase transitions in ferromagnetic shape memory alloys Ni2+xMn1−xGa. Thermal hysteresis and magnetization jumps are clearly resolved by both techniques. Large Barkhausen-like jumps associated with discontinuous phase boundary and martensite twin motion are observed during the austenite–martensite transformation in contrast to the smooth ferromagnetic–paramagnetic transition near the Curie temperature.

Bi-substituted ferrite garnet (R Bi)(3)(M Fe)(5)O-12 epitaxial films with anomalously high (up to 1.2 deg/mum at RT) specific Faraday rotation provide an unique possibility of magneto-optical imaging of magnetic field microdistributions with a sub-micron resolution close to the diffraction limit. In the present work we give a detailed description of the physical principles and various applications of such films in materials science, microelectronics, magnetic testing and nondestructive evaluation (NDE) of defects in both ferromagnetic and non-ferrous metal components. In the latter case eddy-current excitation is used to reveal flaws, cracks and corrosion. The technique is ideal for not only detailed inspections, but also for rapid scanning over large areas to quickly determine structural condition of the part.