TITLE:
Effect of Thickness on Magnetic Dipolar and Exchange Interactions in SmCo/FeCo/SmCo Thin Films
AUTHORS:
Carlos Iván Rodríguez Rodríguez, José Rurik Farías Mancilla, Karla Edith Vega Chavez, Francisco Espinosa Magaña, Sion Federico Olive Méndez, José Trinidad Elizalde Galindo
KEYWORDS:
Exchange Interactions, Dipolar Interaction, Anisotropy
JOURNAL NAME:
Advances in Materials Physics and Chemistry,
Vol.5 No.9,
September
4,
2015
ABSTRACT: SmCo/FeCo/SmCo
trilayer was deposited with two different thickness configurations for soft
phase (FeCo); 50 nm/10 nm/50 nm and 50 nm/25 nm/50 nm were deposited on Si
(111) substrate and Ta (50 nm) seed layer by RF magnetron sputtering in a
pressure, p, of 30 - 35 m Torr. After deposition the films were annealed under
Ar atmosphere at temperature T equal to 923 and 973 for different times
followed by quenching in water. X-ray diffraction patterns were obtained to
identified phase presents and calculate average crystallite size. To study the
effect of configuration thickness in soft phases, DC magnetic measurements were
carried out; the measurements were done in the temperature interval of 300 - 50
K. Hysteresis loops collected at low temperatures exposed an increment in
coercivity with the decrease of T and at same time, presented a “knee” in the
second quadrant of the demagnetization curve, which suggests that the
inter-layer exchange coupling becomes less effective, being more evident for
sample with 50 nm/25 nm/50 nm thickness. Moreover, δM (H) plots were calculated
from magnetic measurements at three different temperatures, T, equal to 300,
150 and 50 K, which corroborates that the dipolar interactions became stronger
when thickness of soft phases increases. Finally, the thickness effect is attributed
to the SmCo5 phase magnetocrystalline anisotropy constant, which is
responsible for the exchange coupling length.