Film Synthesis and Magnetic Properties of Iron Rich Thorium MANGANESE(12) Type Pseudobinary R IRON(12 - T(x) Compounds and Their Nitrides T = Transition Metal R = Rare Earth

For the first time, ThMn_{12 } type pseudobinary R(Fe,T)_ {12} compounds, where R = Sm or Nd and T = Ti, V or Mo, have been sputter synthesized in film form with record high energy product values. Films were synthesized in highly (002) texture mode on polycrystalline Al_2O_3 substrates, where the easy c-axis is highly aligned normal to the film plane, by control of sputtering parameters. Perpendicular to the film plane energy product for a highly (002) textured Sm(Fe,Ti,V)_{12} sample was 21 MGOe at room temperature. For a nitrided highly (002) textured Nd(Fe,Mo)_{12} {rm N}_{rm x} sample, the room temperature coercivity, saturation magnetization, and energy product values were 7.2 kOe, 12.8 kG and 30.2 MGOe respectively, in a direction perpendicular to the film plane. The room temperature anisotropy field value was estimated to be 130 kOe for the same film. In Nd(Fe,Mo) _{12}{rm N}_ {rm x} samples some of the Mo were replaced with Co to enhance the flux density. The room temperature, perpendicular to the film plane energy product was 46.3 MGOe for a sample containing 50% of the Mo replaced with Co. This is the highest room temperature energy product value reported for a nitrided 1-12 sample. Normal to the film plane saturation magnetization and coercivity values were 15.6 kG and 8.7 kOe respectively, for the Co substituted sample. At 10 K, saturation magnetization, coercivity, and energy product increased to 17 kG, 24 kOe and 59.6 MGOe respectively. All these high energy product films were very dense and SEM photographs of fractured sample edges indicated no discernible columnar or void structures. Films were free of alpha-Fe as revealed by the x-ray diffraction patterns. High energy product thin film magnets are useful in many applications, such as small scale electromechanical devices, microwave devices, integrated circuits and small scale permanent magnet geometries.