The influence of Cu doping on structural and magnetic properties of Ni50-xMn36Sn14-yCux, y (x=0, 1,2 and y=1 at. %) ribbons has been investigated. The crystalline structures of the alloys were resolute by X-ray diffraction (XRD). It is found that the addition of Cu for Ni stabilizes austenite phase, whereas, replacing small amount of Cu for Sn stabilizes modulated martensite phase. Differential scanning calorimetry measurements have proved the characteristic transformation temperatures. The transformation temperatures generally rise as increasing the Cu content. Therefore, the magneto structural transition, analysed by vibrating sample magnetometry, is tuned by appropriate Cu doping in the alloys. Likewise, both martensitic and austenitic states exhibit ferromagnetic behaviour.

Co2Fe0.4Mn0.6Si (CFMS) and Co2FeGa0.5Ge0.5 (CFGG) Heusler alloys are among the most promising thin film materials for spintronic devices due to a high spin polarization, low magnetic damping and giant/tunneling magnetoresistance ratios. Despite numerous investigations of Heusler alloys magnetic properties performed up to now, magnetoelastic effects in these materials remain not fully understood; due to quite rare studies of correlations between magnetoelastic and other magnetic properties, such as magnetic dissipation or magnetic anisotropy. In this research we have investigated epitaxial CFMS and CFGG Heusler alloys thin films of thickness in the range of 15–50 nm. We have determined the magnetoelastic tensor components and magnetic damping parameters as a function of the magnetic layer thickness. Magnetic damping measurements revealed the existence of non-Gilbert dissipation related contributions, including two-magnon scattering and spin pumping phenomena. Magnetoelastic constant B11 values and the effective magnetic damping parameter αeff values were found to be in the range of − 6 to 30 × 106 erg/cm3 and between 1 and 12 × 10–3, respectively. The values of saturation magnetostriction λS for CFMS Heusler alloy thin films were also obtained using the strain modulated ferromagnetic resonance technique. The correlation between αeff and B11, depending on magnetic layer thickness was determined based on the performed investigations of the above mentioned magnetic properties.

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