Effect of underlayer thickness on magnetic properties of SmCo film

Abstract

Effect of Sm-Co layer thickness on magnetic properties of crystallized Sm-Co/Cr films Dependence of magnetic properties on magnetic layer thickness in SmCo/Cr films J. Appl. Phys. 85, 6145 (1999); 10.1063/1.370024 SmCo/Cr bilayer films for high-density recording mediaIt is well known that the Cr underlayer plays significant role in the magnetic properties of Co alloy film. In this study, the effects of the underlayer materials such as Cr, Mo, W, W/Cr, and Al and their thickness on the magnetic properties of SmCo films were studied. In the x-ray diffraction diagrams of the SmCo/Cr film and the SmCo/Mo film, only ͑110͒ line of body-centered-cubic crystal structure was observed, while diffraction lines from SmCo phase could not be observed. The oval shaped grains were observed on the surface of Cr underlayer and the Mo underlayer when the thickness was thicker than 100 nm. The coercivity of the SmCo/Cr film and the SmCo/Mo film with thickness over 100 nm was higher than 3 kOe and the squareness ratio and the coercivity squareness ratio was above 0.8 and 0.9, respectively. These results indicate the Cr underlayer and the Mo underlayer are suitable for SmCo layers in order to increase the coercivity and the SmCo/Cr film and the SmCo/Mo film are good candidates for high density recording media.

Microstructure and magnetic properties studies of SmCo5 thin films grown on MgO and glass substrates

“…It has been reported that the (11 2 0) textured SmCo 5 film showed higher intrinsic in-plane coercivity compared to the (11 0 0) textured SmCo 5 films, probably because of a finer microstructure [15]. From 1990s, it has been found that the Cr underlayer can induce large in-plane coercivity in SmCo films [16][17][18][19][20][21][22][23]. Moreover, high temperature post-annealing and substrate heating have been found to be useful for enhancement of coercivity in SmCo films due to better crystallization of SmCo phases [21,24,25].…”

“…It has been found that appropriate single crystal substrates such as MgO (1 0 0), MgO (11 0) [4][5][6][7][8] and Si (1 0 0) [9][10][11][12] can lead to epitaxial or highly textured growth of SmCo 5 films with high coercivity values. On the other hand, for practical reason, many researchers have dedicated themselves to develop techniques for high coercivity SmCo 5 films grown on amorphous or polycrystalline substrates such as glass, Al and Al 2 O 3 [13][14][15][16][17][18][19][20][21][22][23][24][25][26]. In the early 1980s, amorphous SmCo films with small in-plane intrinsic coercivity (o3 kOe) were obtained by direct deposition on glass substrates [13,14].…”

Microstructure and Magnetic Anisotropy of SmCo‐Based Films Prepared via External Magnetic Field Assisted Magnetron Sputtering

“…have a significant effect on the magnetic anisotropy and microstructure of SmCo‐based films. [ 13–16 ] These inserting buffer layers have a proper lattice mismatch with the SmCo layer, which can provide good adhesion to the substrates, compensate for the thermal mismatches between the substrate and SmCo layer, and promote epitaxial growth of the hexagonal Sm–Co films parallel to the c ‐axis. Sayma et al obtained the SmCo 5 (0001) texture with out‐of‐plane magnetic anisotropy by adding a thick Cu buffer layer (about 100 nm).…”

Beneficial effect of rapid recurrent thermal annealing on magnetic properties of SmCo-based films

“…Lots of efforts have been put into the research about the sputtered SmCo-based films [4][5][6][7][8][9][10]. It is found that the SmCo-based films prepared by conventional sputtering and subsequent annealing process are almost amorphous and the crystallization is hard to be completed, which decides that the magnetic properties of these SmCo-based films are insensitive to heat treatment [4,5]. Consequently, the SmCo-based films have been developed to be deposited on heat substrates directly and well-crystallized films with good magnetic properties are observed [6][7][8].…”