Many transition metal oxides belong to this class which may be subdivided according to their behavior, e.g. high-T c, spintronic materials, multiferroics, Mott insulators, spin Peierls materials, heavy fermion materials, quasi-low-dimensional materials, etc. The single most intensively studied effect is probably high-temperature superconductivity in doped cuprates, e.g. La 2−x Sr x CuO 4. Other ordering or magnetic phenomena and temperature-induced phase transitions in many transition-metal oxides are also gathered under the term "strongly correlated materials."