perovskites bandgap semiconductive austenite temperature Mn3O4 180QdgC DBTT ferroelectrics liquidus Co3O4 thermoelectrics HQdgform Desnica perovskite magnetocrystalline thermotropic superconducting superhard pyroprocessing YBa2Cu3O7 PCMs aluminide paramagnetic eutectic AlAs superconductors TQundH YBCO cristobalite monofluoride ferromagnetism NP0 130QdgC dielectric magnetization cuprate superalloys Tc