Simultaneous detection of perpendicular and in-plane magnetization component in a [Co/Pd]n perpendicular magnetic recording media

Abstract

Hall effect measurement has been used to detect the perpendicular and in-plane magnetization components simultaneously in a [Co/Pd]n multilayer thin film with strong magnetic anisotropy along the direction perpendicular to the film plane. The angle between the driving current direction and the in-plane projection of the applied magnetic field was varied to investigate the contribution of in-plane magnetization component to the measured Hall voltage. Hall voltage under the canted magnetic field revealed that the output is the superposition of the anomalous Hall effect (AHE) due to the perpendicular component of magnetization and the planar Hall effect (PHE) due to the in-plane magnetization component. Odd symmetry characteristics of AHE and even symmetry characteristics of PHE with respect to applied field have been applied to extract the Hall voltage contributed by the two different magnetization components from their combined characteristic. Anomalous Hall voltage from the perpendicular magnetization component exhibited an irreversible hysteresis loop while that from the in-plane magnetization component was found almost reversible with respect to applied magnetic field. The method was effective to evaluate the in-plane component of magnetization in an ultrathin film under the canted magnetic field.

Temperature and Co thickness dependent sign change of the anomalous Hall effect in Co/Pd multilayers: An experimental and theoretical study

“…The anomalous Hall effect (AHE) 1,2 of ultra-thin multilayered (ML) films with large perpendicular magnetic anisotropy (PMA) has recently attracted considerable attention due to its potential applications for high-density magnetic recording technology, such as recording media, magnetic random access memory (MRAM), and magnetic sensors. [3][4][5][6][7] For applications, parameters like squareness and coercivity of the magnetic hysteresis curve and the amplitude of the AHE voltage are desired to be tunable. For instance, the coercivity has to be as small as possible when it is used for magnetic field sensor elements, but it has to be moderately large when it is used for recording media elements.…”

Planar Hall effect in magnetite (100) films

“…The PHE was previously employed in ferromagnetic metals, as a tool to study inplane magnetization 2,3 , out-of-plane magnetization 4 and it has also been studied in lowfield magnetic sensor applications 5 . Recently, a large switching signal in the PHE has been measured in (Ga,Mn)As thin film devices and LaSrMnO 3 films 6,7 , this effect is observed to be 4 orders of magnitude higher than previously observed in ferromagnetic metals and it is called the giant planar hall effect (GPHE).…”

Study of magnetization reversal phenomena in CoCrTaPt perpendicular recording thin film media in a tilted magnetic field

“…, there is a simultaneous change in M J components, which can easily be detected in a Co/Pd multilayered structure but not in the granular-type CoCr-based materials [3]. This might be due to the very small mobility difference of the deflected carriers with up and down spin, which makes the planar Hall voltage negligibly small and undetectable in the granular system.…”