Ion irradiation induced direction of collapsed hard-magnetization axis in thin Co films

• Autor(a) principal: Azeredo, Lucas Felipe Santos de
• Data de Publicação: 2023
• Outros Autores: Geshev, Julian Penkov, Grande, Pedro Luis, Andrade, Antonio Marcos Helgueira de
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/268524
• topic: Filmes finos; Bombardeamento de ions; Anisotropia magnética; Campos magnéticos

A number of polycrystalline films feature distinct sharp peaks in the angular variations of their in-plane major-loop remanent magnetization and coercivity, centered 90◦ off the easy-axis position, a property referred to as hard-axis collapse. In such systems a striking phenomenon, recoil-curve overshoot (RCO), recoil mag netization branches that lie outside the major loop, was recently reported, resulting in a significantly greater recoil loop area compared with that of the respective major loop. In the present work pieces of polycrystalline magnetron-sputtered Co films were subjected to Ne+ bombardment in vacuum at different ion fluences in the presence of magnetic field Hib applied along different in-plane directions. Ion irradiation at a certain fluence range results in films with easy-magnetization directions parallel to that of Hib. Moreover, the same holds for posterior sequential irradiations. The films’ hard-magnetization axes are always collapsed, accompanied by significant RCO as well. The analysis and interpretation of our data strongly indicate that both hard-axis collapse and RCO result predominantly from a domain splitting when the measurement magnetic field is nearly perpendicular to the grain’s easy axis during demagnetization.