Structural and magnetic properties of SmCo-based magnetic films grown by electron-beam evaporation

Sub-micron thick Sm–Co films (200 and 300 nm) with selective phase composition are grown on Si (100) substrates by electron-beam evaporation using Sm-lean alloy targets such as Sm₄Co₉₆ and Sm₈Co₉₂. The structural and magnetic properties of Sm–Co films are characterized by x-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and super-conducting quantum interference device (SQUID) magnetometer. The Sm–Co films obtained with the Sm₄Co₉₆ target exhibit Sm₂Co₁₇ as a prominent phase; while the films produced with the Sm₈Co₉₂ target show Sm₂Co₇ as a major phase. Both the Sm–Co films reveal granular morphology; however, the estimated grain size values are slightly lower in the case of Sm₂Co₇ films, irrespective of their thicknesses. Coercivity (H_c) values of 1.48 and 0.9 kOe are achieved for the as-grown 200-nm thick Sm₂Co₁₇ and Sm₂Co₇-films. Temperature-dependent magnetization studies confirm that the demagnetization behaviors of these films are consistent with respect to the identified phase composition. Upon rapid thermal annealing, maximum H_c value of 8.4 kOe is achieved for the 200 nm thick Sm₂Co₁₇-films. As far as e-beam evaporated Sm–Co films are concerned, this H_c value is one of the best values reported so far. - Highlights: • Electron-beam evaporation was exploited to grow sub-μm thick Sm–Co films. • Sm₂Co₇ and Sm₂Co₁₇ magnetic phases were crystallized using Sm-lean alloy targets. • Both 200 and 300-nm thick Sm–Co films revealed distinct granular morphology. • Sm–Co films of lower thickness exhibited high H_c and low M_s and vice-versa. • Coercivity value of 8.4 kOe achieved for the 200-nm thick Sm₂Co₁₇-films after RTA