Artículos de revistas
Local and global magnetic properties of Zn1-xCoxO and Mn-doped GaAs thin films
Fecha
2006-10-01Registro en:
IEEE Transactions on Magnetics. Piscataway: IEEE-Inst Electrical Electronics Engineers Inc., v. 42, n. 10, p. 2700-2702, 2006.
0018-9464
10.1109/TMAG.2006.878845
WOS:000240888700148
1134426200935790
Autor
Universidade Estadual de Campinas (UNICAMP)
Univ Puerto Rico
Universidade Estadual Paulista (Unesp)
Lab Nacl Luz Sincrotron
San Diego State Univ
Institución
Resumen
Amorphous and crystalline thin films of Mn-doped(0.5%-10%) GaAs and crystalline thin films of Zn1-xCoxO(x = 3%-20%) were investigated by means of magnetic susceptibility and electron spin resonance (ESR). For the Mn-doped GaAs samples, our results show the absence of ferromagnetic ordering for the amorphous films in the 300 > T > 2 K temperature range, in contrast to the ferromagnetism found in crystalline films for T-C < 110 K. A single ESR line with a temperature independent g-value (g similar to 2) is observed for the amorphous films, and the behavior of this ESR linewidth depends on the level of crystallinity of the film. For the Mn-doped GaAs crystalline films, only a ferromagnetic mode is observed for T < TC when the film is ferromagnetic. Turning now the Zn1-xCoxO films, ferromagnetic loops were observed at room temperature for these films. The magnetization data show an increasing of the saturation magnetization M. as a function of x reaching a maximum value for x approximate to 10%. ESR experiments at T = 300 K in the same films show a strong anisotropic ferromagnetic mode (FMR) for x = 0.10.